Modal Shift Report in the Boulder Valley 2023 Travel Diary Study 1241 John Q. Hammons Dr, Suite 03
Madison, WI 53717
info.polco.us • 608-709-8683
Modal Shift in the Boulder Valley
2023 Travel Diary Study
Report of Results
April 2024
Modal Shift in the Boulder Valley: 1990-2023
Table of Contents
EXECUTIVE SUMMARY ........................................................................................................................ I
Background .............................................................................................................................................. i
Modal Shift of All Trips ......................................................................................................................... ii
Modal Split of the Work Commute ..................................................................................................... iv
Mode Use ................................................................................................................................................ iv
Trip Characteristics ................................................................................................................................ v
STUDY RESULTS ..................................................................................................................................... 1
Background ............................................................................................................................................. 1
Modal Shift of All Trips ......................................................................................................................... 2
Modal Split of the Work Commute ...................................................................................................... 8
Telecommuting ..................................................................................................................................... 12
Modal Split of University of Colorado Students .............................................................................. 14
Trip Characteristics .............................................................................................................................. 15
Purpose of Travel ................................................................................................................................. 31
APPENDIX A. NATIONAL TRAVEL DATA .................................................................................... 35
APPENDIX B. MODAL SPLIT BY CHARACTERISTICS .............................................................. 38
APPENDIX C. TRANSPORTATION MARKET SEGMENTATION ........................................... 47
Key Characteristics of the Transportation Segments ...................................................................... 48
APPENDIX D. REFERENCES ............................................................................................................... 54
APPENDIX E. STUDY METHODOLOGY ......................................................................................... 55
Study Design ......................................................................................................................................... 55
Analysis of Results ............................................................................................................................... 56
APPENDIX F. DATA COLLECTION MATERIALS ........................................................................ 60
Modal Shift in the Boulder Valley: 1990-2023
Page i
Executive Summary
BACKGROUND
The 2023 Travel Diary Study is the thirteen replication of an effort that began in 1990 to assess the
Boulder Valley residents’ travel patterns and choices of transportation modes. The study is intended
to support transportation planning by providing information on travel patterns and report to City
staff and council members on the effectiveness of City programs aimed at reducing single-occupancy
vehicle (SOV) travel and related vehicle miles of travel (VMT) and greenhouse gas (GHG) emissions.
The four decades trend line helps measure the City’s progress in encouraging a shift away from SOV
trips, which was a major objective in the 1989 Transportation Master Plan’s (TMP). Later updates of
the TMP specified the objective of reducing the SOV modal share to 25% of all trips by the year 2025,
and most recently to 20% by 2030 in the 2019 TMP. In 1990, the first year of the travel diary study,
44% of all trips were made by driving alone. Achieving an SOV modal share of 20% by the year 2030
would mean a 24% shift in the proportion of SOV trips made from 1990 to 2030, or a 0.6% shift per
year.
As in previous iterations, Boulder Valley residents were defined as residents residing in ZIP codes
80301 through 80305. This delineation mirrors the criteria utilized in the Boulder Resident Survey,
most recently administered in 2023. On the other hand, the Boulder Valley Employee Survey, last
conducted in 2022, characterizes Boulder Valley employees as individuals employed by businesses
with addresses falling within ZIP codes 80301 through 80310.
Participants in the Travel Diary Studies were asked to keep a log or “diary” of their travel for one
randomly assigned day during the beginning of October 2023. For every trip made during the 24-
hour period, respondents record the origin and destination of the travel, the travel mode used, the
time of day, the number of people in the vehicle (if applicable), and the distance traversed. A trip was
defined as any “one-way travel from one point to another that takes you farther than one city block
(about 200 yards) from the original location.”
The study members were also asked to complete a survey regarding their household characteristics
including several items related to travel, such as vehicles, bicycles, e-bikes and e-scooters present in
the household, receipt of deliveries, work location, possession of bus passes, memberships in bike, e-
bike, e-scooter or car shares, and general socioeconomic demographic characteristics.
The 2023 Travel Diary Study results are based on 998 Boulder Valley residents’ records of their
travel. With a sample size of close to 1,000 in each study year, the margin of error around the results
is ±1.3% per year. Thus, for a difference to be statistically significant between years there must be a
shift of at least 2.6% (1.3% around each study year).
Modal Shift in the Boulder Valley: 1990-2023
Page ii
MODAL SHIFT OF ALL TRIPS
“Modal split” or “modal share,” is a method of dividing travel into all available transportation modes
and determining the percentage of trips made or miles traveled by each mode. For the Boulder Valley
Travel Diary Study, the transportation modes are classified as single-occupancy vehicle (SOV),
multiple-occupancy vehicle (MOV), transit or high-occupancy vehicle, school bus, foot and bicycle. A
comparison of the mode choices from 1990 to 2023 provides information on modal “shift,” that is,
the shift of trips or miles traveled from one mode to another. This “shift” is measured as the difference
between 1990 to 2023 in the percent of trips or miles by each mode.
The figure below shows the modal split of all trips made by respondents in every study year.
Compared to 1990, significant shift in trips was observed in three categories:
• Single-Occupancy Vehicle, -9.1%
• Multiple-Occupancy Vehicle, -4.6%
• Bicycle +8.6%
Figure 1: Modal Split of All Trips, 1990-2023
*In 2023 it included E-Bike and E-scooter: 4.4%.
44.2%
42.3%
40.5%41.5%40.4%41.5%
39.0%38.4%37.1%35.9%36.1%36.7%
35.1%
26.3%25.7%25.6%25.6%25.0%23.8%23.5%
25.0%23.7%
22.1%21.3%21.7%
1.6%2.2%2.9%2.8%4.1%4.2%4.6%4.0%
5.4%4.9%3.7%5.0%4.0%
9.1%
12.1%11.3%
9.2%8.2%
10.0%
14.0%13.6%
15.9%
18.7%
20.3%
17.0%17.7%18.2%17.1%
19.2%20.4%21.4%
19.8%18.6%18.9%
17.9%
20.3%
17.7%
20.0%21.6%
0%
10%
20%
30%
40%
1990 1992 1994 1996 1998 2000 2003 2006 2009 2012 2015 2018 2023% of TripsSingle-Occupancy Vehicle
Multiple-Occupancy Vehicle
Pedestrian
Bicycle*
Transit
Modal Shift in the Boulder Valley: 1990-2023
Page iii
The 2019 TMP includes the objective of achieving an SOV modal share of 20% by the year 2030; this
would mean a 24% shift in the proportion of SOV trips made from 1990 to 2030, or an average annual
shift of 0.6%, assuming equal progress throughout the forty-year span. In the figure below, the 2019
TMP target is plotted with the observed shift. As can be seen, the observed modal shift in recent years
has not quite kept pace with the 2019 TMP objective, with no significant change observed from 2012
to 2023.
Figure 2: Percent of SOV Trips: Observed Versus Desired Shift, 1990-2023
Changes in Boulder citizens’ travel behavior cannot be solely attributed to the City’s interventions,
as regional and national transportation trends also impact travel behavior. The most recent national
data comes from the National Household Travel Survey, conducted in 2022 by the Federal Highway
Administration.
• Nationwide, there was a 0.04% annual shift away from trips made via private vehicles
(87.7% in 1990, 86.8% in 2022) over the last two decades. However, among Boulder
Valley residents, there was an annual average decrease of 0.60% from 1990 to 2023
(70.5% in 1990, 56.8% in 2023).
• The proportion of trips made by transit stayed relatively flat nationwide (1.8% in 1990;
1.9% in 2022). In Boulder there was a 2.4% shift toward public transit in the same
period (1.6% in 1990; 4.0% in 2023).
• Examining the modal split of miles traveled, nationally there was a 5% decrease in the
miles traveled per person by private vehicle from 1990 to 2022. In Boulder there was
a 10% shift away from miles traveled via private vehicles (88% in 1990, 78% in 2023).
• The proportion of miles traveled via transit decreased nationwide, from 2.1% in 1990
to 1.2% in 2022, while in Boulder the percentage of miles traveled via transit increased,
from 4.1% in 1990 to 7.7% in 2023.
35%
24%
15%
20%
25%
30%
35%
40%
45%
50%
1990 1992 1994 1996 1998 2000 2003 2006 2009 2012 2015 2018 2023% of TripsBaseline SOV use
Observed shift
2019 TMP Update Goal Shift
2019 TMP Update 2035 Goal SOV Use
Modal Shift in the Boulder Valley: 1990-2023
Page iv
MODAL SPLIT OF THE WORK COMMUTE
The figure below shows the percentage of work commute trips made by respondents via SOV and
bicycle in every study year. Smaller changes were observed over the study period in multiple-
occupancy vehicle trips (between 10% in 1990 and 5% in 2023), transit (between 4% in 1990 and
8% in 2023) and pedestrian trips (between 9% in 1990 and 11% in 2023). Compared to 1990,
significant shift was observed in two categories in 2023:
• Single-Occupancy Vehicle, -20.0%
• Bicycle, +19.4%
Bicycle trips showed a large increase in modal share from 2012 to 2015, dropped slightly in 2018
and moderately in 2023. Over these years SOV modal share experienced a large drop between 2012
and 2018 followed by a large increase between 2018 and 2023.
Figure 3: Modal Split of Work Commute Trips, SOV vs. Bicycle 1990-2023
*In 2023 it included E-Bike and E-scooter: 1.8%.
The significant increase in SOV modal share between 2018 and 2023 may be linked to the rise in
teleworking and impacts of COVID-19 pandemic. If respondents who transitioned to working from
home were more likely to use alternative modes of transportation, the increase in SOV share among
those who still commute to work could be attributed to the removal of individuals who previously
used alternative modes.
Figure 4: Telecommuting on Assigned Travel Day, 1996-2023
66.6%
60.2%59.8%
64.8%62.3%
57.7%
49.6%52.7%
47.4%48.5%
39.8%
34.3%
46.6%
10.6%
14.1%12.4%12.3%9.9%
15.6%
21.2%20.5%23.3%
26.5%
35.3%33.7%
30.0%
0%
10%
20%
30%
40%
50%
60%
70%
1990 1992 1994 1996 1998 2000 2003 2006 2009 2012 2015 2018 2023Percent of Work Commute TripsSingle-Occupancy Vehicle
Bicycle*
13.6%11.0%10.4%12.2%12.0%
8.1%10.8%11.4%12.6%
24.6%
0%
10%
20%
30%
1996 1998 2000 2003 2006 2009 2012 2015 2018 2023
Modal Shift in the Boulder Valley: 1990-2023
Page v
MODE USE
The proportion of people making at least one trip on the assigned travel day by each mode
throughout the study period is shown below. Over the study period, the percentage of participants
making any trips by SOV or MOV has declined, while the proportion making any trips via transit or
by bicycle has increased. The proportion of people with at least one SOV trip on the assigned day
remained stable in 2023 in comparison with 2018, while the proportion of people with at least one
MOV slightly decreased from 5 years ago.
Figure 5: Study Participants Making At least One Trip by Mode, 1990-2023
TRIP CHARACTERISTICS
The information recorded on the travel diary can be used to characterize the trip -making behavior
of Boulder residents. In 2023:
• The average number of trips per day per person was 5.1.
• The average number of miles traveled per day per person was 20.2 miles.
• The percent of people who did not leave the house on assigned travel day was 7.6%.
• The average estimated trip distance was 4.3 miles.
• The average estimated trip duration was 18.4 minutes.
Compared to national data, Boulder residents make shorter trips (4.3 miles for Boulder residents in
2023 compared to 12.5 miles in 2022 for U.S. residents).
The average work commute trip for Boulder residents in 2023 was 5.5 miles in distance and 20
minutes in duration. The average work commute for U.S. residents in 2022 was 13.7 miles and 28
minutes.
64.6%
60.0%
63.0%
60.2%59.5%
62.8%
56.6%56.8%
53.6%
49.5%48.1%
53.4%53.4%47.5%
44.2%
47.1%46.9%
43.7%43.1%
40.6%
43.3%
38.6%
32.4%
35.9%37.2%
36.7%
4.8%6.0%7.7%8.6%10.3%11.5%11.2%9.2%
12.5%11.0%10.7%
13.3%
9.6%
33.0%34.8%
36.9%
39.9%39.1%
36.9%
34.8%34.6%33.0%
30.8%
37.2%
37.5%
15.2%
20.9%19.8%
16.6%15.0%
17.1%
23.2%
20.4%
23.9%25.2%
32.7%
27.2%
21.3%
0%
10%
20%
30%
40%
50%
60%
1990 1992 1994 1996 1998 2000 2003 2006 2009 2012 2015 2018 2023
Single-Occupancy Vehicle
Multiple-Occupancy
Vehicle
Bicycle
Pedestrian
Transit
Modal Shift in the Boulder Valley: 1990-2023
Page 1
Study Results
BACKGROUND
The Travel Diary Study is a periodic survey of Boulder Valley residents’ travel patterns and mode
selection. The baseline study was conducted in 1990 and has been re-implemented every two to five
years since then. The study is designed to report to City staff and Council members on the
effectiveness of City programs aimed at reducing single-occupancy vehicle (SOV) travel, and to
provide information on travel patterns useful for future transportation planning.
The 2023 Travel Diary Study is the thirteenth replication of the survey since the baseline study. This
long trend line is useful in measuring the City’s progress in mode shift away from SOV trips, as one of
the original Transportation Master Plan’s (TMP) major objectives was to shift “15% of all trips
currently made by single-occupant autos to other forms of transportation, including ridesharing,
transit, walking, and bicycling” by the year 2010. In 1990, the first year of the travel diary study, 44%
of all trips were made by driving alone. The 1996 TMP modified the objective to a target of reducing
the SOV modal share to only 25% of all trips by the year 2020 and the 2003 and 2008 update
extended the target year to 2025. Reflecting the city’s Sustainability Framework and Climate
Commitment, the 2014 TMP established a more aggressive target of a 20% SOV mode share by 2035.
More recently, the 2019 TMP modified the target year to 2030. This target is now the standard against
which these study results are measured. Achieving an SOV modal share of 20% by the year 2030
would mean a 24% shift in the proportion of SOV trips made from 1990 to 2030, or a 0.6% shift per
year.
Participants in the Travel Diary Studies were asked to keep a log or “diary” of their travel for one
randomly assigned day during the beginning of October (or a replacement week if necessary). For
every trip made during the 24-hour period, they recorded the origin and destination of the travel, the
travel mode used, the time of day, the number of people in the vehicle (if applicable), and the number
of miles or blocks traveled during each trip. A trip was defined as any “one-way travel from one point
to another that takes you farther than one city block (about 200 yards) from the original location.”
The participants were also asked to complete a survey regarding their adult household members’
typical primary modes of travel, locations of work/school, number of vehicles, and general
socioeconomic information about the household and the study participant (see Appendix F. Data
Collection Materials for copies of the survey materials).
The 2023 Travel Diary Study results are based on 998 Boulder Valley residents’ records of their
travel. Study results were statistically weighted so that demographics of respondents matched
population demographics. Details about the methodology used to select individuals to participate in
the study and how they recorded their travel can be found in Appendix E. Study Methodology.
With a sample size of about 1,000 in each past study year, the margin of error around the results is
±1.3% per year. Thus, for a difference to be statistically significant between years there must be a
shift of at least 2.6% (1.3% around each study year).
Modal Shift in the Boulder Valley: 1990-2023
Page 2
MODAL SHIFT OF ALL TRIPS
Transportation mode choice, referred to as “modal split” or “modal share,” is a method of classifying
all travel completed in a specified time into all available transportation modes. In this study “modal
split” is reported two ways: the proportion of total trips and proportion of total miles by mode. The
mode classifications are single-occupancy vehicle (SOV), multiple-occupancy vehicle (MOV)1, transit
or high-occupancy vehicle, school bus, foot and bicycle.
A comparison of the mode choices from 1990 to 2023 provides information on modal “shift,” that is,
the shift of trips or miles traveled from one mode to another. This “shift” was measured as the
difference in the proportion of trips from 1990 to 2023 (change in percent). The modal split of trips
as observed in the 2023 Travel Diary is shown in Figure 6 while the modal shift of trips from 1990 to
2023 by Boulder Valley residents is presented in Figure 7 on the next page.
Figure 6: Modal Split of All Trips, 2023
* In 2023 it included E-Bike and E-scooter: 4.4%.
1 A single-occupancy vehicle refers to an automobile, van, truck or motorcycle which has only one occupant; a multiple -
occupancy vehicle is an automobile, truck or motorcycle with more than one occupant (truck and motorcycle trips make up
a very small proportion of the trips made.)
Multiple-
Occupancy
Vehicle, 21.7%
Single-
Occupancy
Vehicle, 35.1%
Transit, 4.0%
Bicycle*, 17.7%
Foot, 21.6%
Modal Shift in the Boulder Valley: 1990-2023
Page 3
Over the entire study period, the proportion of all trips made by driving alone has shifted 9%, about
half of which occurred in the early 1990s. In 2023, SOV trips accounted for about 35% of all trips
made by Boulder residents, down from about 44% in 1990 and like what had been observed since
2012. Transit trips have doubled over that same period, increasing from less than 2% in 1990 to
about 4% in 2023. Large gains were observed in the proportion of trips made by bicycle over the
previous 3 decades, from 9% in 1990 to 18% in 2023.
The proportion of trips made via MOV has remained fairly constant from 1990 until 2006. However,
from 2006 to 2023 there was a 3% decrease in MOV trips. In 2023, 22% of all trips were made in
personal vehicles with more than one person, down from 26% in 1990. Nearly a third of those MOV
trips included at least one child in the vehicle, while just over two-thirds included only adults.
Figure 7: Modal Split of All Trips, 1990-2023
Travel
Mode
Percent of Trips* Change
1990 to
2023 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
SOV 35.1% 36.7% 36.1% 35.9% 37.1% 38.4% 39.0% 41.5% 40.4% 41.5% 40.5% 42.3% 44.2% -9.1%
MOV 21.7% 21.3% 22.1% 19.6% 23.7% 25.0% 23.5% 23.8% 25.0% 25.6% 25.6% 25.7% 26.3% -4.6%
Transit 4.0% 5.0% 3.7% 4.9% 5.4% 4.0% 4.6% 4.2% 4.1% 2.8% 2.9% 2.2% 1.6% +2.2%
School Bus 0.0% 0.0% 0.0% 0.6% 0.1% 0.1% 0.3% 0.7% 0.7% 0.5% 0.5% 0.7% 0.6% -0.6%
Bicycle** 17.7% 17.0% 20.3% 18.7% 15.9% 13.6% 14.0% 10.0% 8.2% 9.2% 11.3% 12.1% 9.1% +8.6%
Foot 21.6% 20.0% 17.7% 20.3% 17.9% 18.9% 18.6% 19.8% 21.4% 20.4% 19.2% 17.1% 18.2% +3.4%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of
Trips 4,406 4,094 5,767 4,835 5,505 6,081 6,380 6,791 5,987 6,454 6,723 6,681 7,355
Modes with shifts that are statistically significantly different between 1990 and 2023 are shaded.
* These estimates have a margin of error of ±1.3% using a 95% confidence interval.
** In 2023 included 4.4% corresponding to E-bike and E-scooter.
Modal Shift in the Boulder Valley: 1990-2023
Page 4
The 2019 TMP includes the objective of achieving an SOV modal share of 20% by the year 2030; this
would mean a 24% shift in the proportion of SOV trips made from 1990 to 2030, or an average annual
shift of 0.6%, assuming equal progress throughout the forty-year span. In the figure below, the 2019
TMP target is plotted with the observed shift. As can be seen, the observed modal shift has not quite
kept pace with the 2019 TMP objective in recent years, with no significant change observed from
2012 to 2023.
Figure 8: Percent of SOV Trips: Observed Versus Desired Shift, 1990-2023
35%
24%
15%
20%
25%
30%
35%
40%
45%
50%
1990 1992 1994 1996 1998 2000 2003 2006 2009 2012 2015 2018 2023Percent of TripsBaseline SOV use
Observed shift
2019 TMP Update Goal Shift
2019 TMP Update 2030 Goal SOV Use
Modal Shift in the Boulder Valley: 1990-2023
Page 5
Changes in Boulder citizens’ travel behavior cannot be solely attributed to the City’s interventions,
as regional and national transportation trends also impact travel behavior. However, the national
trends observed demonstrated only a slight reduction in “privately owned vehicle” (POV) use, which
includes both SOVs and MOVs, between 1990 and 2009.2 Figure 9 below compares the change
observed in Boulder from 1990 to 2023 to that observed in the nation from 1990 to 2022.
Nationwide, there was a 0.7% shift away from trips made via private vehicles (87.6% in 1990, 86.9%
in 2022) over a 32-year period, which translates to an average annual decrease of 0.02%. However,
among Boulder Valley residents, there was an 11% shift observed (70.5% in 1990, 56.8% in 2023)
in POV use over a 33-year period, an average annual decrease of 0.42%.
The proportion of trips made on transit remained virtually unchanged nationally (1.8% in 1990;
1.5% in 2023), while in Boulder there was a 2.5% shift toward public transit (1.6% in 1990; 4.0% in
2023).
Figure 9: Percent of All Trips: Boulder Compared to the U.S., 1990-2023
2 Appendix A. National Travel Data contains additional detail on the comparisons made in Figure 9.These data come from the
1990 and 1995 Nationwide Personal Transportation Study and the 2001, 2009 and 2023 National Household Travel Study
(NHTS).
57%
87%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
'90'91 '92'93'94'95 '96'97'98'99 00 '01'02'03 '04'05'06 '07'08'09'10 '11'12'13'14 '15'16'17'18 '19'20'21'22 '23Percent of TripsBoulder: Personal Vehicles
U.S.: Personal Vehicles
Boulder: Transit
U.S.: Transit
Modal Shift in the Boulder Valley: 1990-2023
Page 6
Modal share estimates using miles traveled show larger shares for the motorized vehicles because
these vehicles are used to traverse greater distances. From 1990 to 2012, there had been no
significant change observed in the SOV share of miles traveled, with some mild variation from year
to year. However, in 2015 there was a decrease in the number of miles traveled by SOV which was
maintained in 2018 and 2023. However, while MOV miles increased from 2012 to 2015, they dropped
somewhat from 2015 to 2023.
There has been a shift of about 5% in the proportion of miles traveled by bicycles in the study period,
increasing from 4.9% of miles in 1990 to 10.3% of miles in 2023. Likewise, the number of miles
traveled by transit has also increased over the study period, about 3.5% from 1990 to 2023 (4.1% in
1990 to 7.6% in 2023).
Figure 10: Modal Split of All Miles, 1990-2023
Travel
Mode
Percent of Miles* Change
1990 to
2023 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
SOV 41.8% 41.6% 41.9% 49.6% 46.1% 46.9% 44.0% 49.1% 48.1% 45.2% 46.2% 48.0% 50.0% -8.2%
MOV 36.1% 35.2% 38.7% 30.5% 35.9% 36.3% 39.5% 35.9% 35.6% 41.3% 38.6% 37.3% 37.7% -1.6%
Transit 7.6% 10.5% 7.8% 6.6% 6.9% 5.7% 5.5% 6.5% 7.0% 5.7% 6.4% 6.2% 4.1% 3.5%
School Bus 0.1% 0.0% 0.0% 0.5% 0.5% 0.1% 0.2% 0.4% 0.6% 0.2% 0.2% 0.5% 0.2% -0.1%
Bicycle** 10.3% 9.2% 8.5% 9.3% 8.1% 7.2% 7.7% 4.7% 4.6% 4.3% 5.6% 5.4% 4.9% 5.4%
Foot 4.1% 3.5% 3.1% 3.4% 2.5% 3.7% 3.0% 3.5% 4.1% 3.2% 2.9% 2.5% 3.0% 1.1%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of
Miles 19,023 17,411 25,358 18,269 27,016 25,756 31,248 28,689 25,562 30,042 30,300 29,761 29,634
Modes with shifts that are statistically significantly different between 1990 and 2023 are shaded.
Modes with shifts that are statistically significant different between 2018 and 2023 are bolded.
* These estimates have a margin of error of ±1.3% using a 95% confidence interval.
** In 2023 included 1.8% corresponding to E-bike and E-scooter.
As with the modal split of trips, the reduction in SOV miles can be compared to the 2019 TMP
objective (Figure 11), assuming that the objective of a 24% shift in the proportion of trips made by
SOV can be translated as an objective of a 24% shift in the proportion of miles traveled by SOV. When
miles are used as the unit of analysis, it can again be observed that the modal shift of miles has not
yet met the TMP objective. There tends to be more variability in the proportion of miles traveled by
different modes than there is in the proportion of trips.
Modal Shift in the Boulder Valley: 1990-2023
Page 7
Figure 11: Percent SOV Miles: Observed Versus Expected Shift, 1990-2023
Figure 12 shows a comparison of the percent of miles traveled in the nation between 1990 and 2022,
and in Boulder Valley between 1990 and 2023, by mode. The proportion of miles traveled by private
vehicles dropped in the U.S., from 88% of miles in 1990 to 83% in 2022. The Boulder trend was also
a declining one, from 88% of miles in 1990 to 78% in 2023. The proportion of miles traveled via
transit decreased slightly nationwide, from 2.1% in 1990 to 1.2% in 2023, while in Boulder the
percent of miles traveled via transit increased, from 4.1% in 1990 to 7.6% in 2023.
Figure 12: Percent of All Miles: Boulder Compared to the U.S., 1990-2023
42%
32%
20%
25%
30%
35%
40%
45%
50%
55%
1990 1992 1994 1996 1998 2000 2003 2006 2009 2012 2015 2018 2023
Baseline SOV use
Observed shift
2019 TMP Update Goal Shift
2019 TMP Update 2030 Goal SOV Use
78%
83%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
'90'91 '92'93'94 '95'96'97 '98'99 00 '01'02'03 '04'05'06 '07'08'09 '10'11'12 '13'14'15 '16'17'18 '19'20'21'22'23Percent of MilesBoulder: Personal Vehicles
U.S.: Personal Vehicles
Boulder: Transit
U.S.: Transit
Modal Shift in the Boulder Valley: 1990-2023
Page 8
MODAL SPLIT OF THE WORK COMMUTE
Trips made as part of the work commute were identified for special analysis, including trips directly
between home and work and trips linked during the work commute.3 As not all respondents had a
work commute, the data in the following tables are based on a smaller number of respondents and
trips, are less stable from year to year and have a higher margin of error (about ±4%).
The SOV modal share of work commute trips decreased from 1990 to 2023 by 20% (see Figure 13),
with a large decrease from 2012 to 2018 of about 14% and a large increase of the same magnitude
between 2018 and 2023 The transit share has varied over the years but has shown a more stable
upward trend since 1996; peaking at 12.3% of trips in 2018. The proportion of work commute trips
made by bicycling, which has increased over the study period, had a large increase from 2012 to 2015
followed by moderate decreases in 2018 and 2023.
Figure 13: Modal Split of Trips for the Work Commute, 1990-2023
Travel
Mode
Percent of Trips* Change
1990 to
2023 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
SOV 46.6% 34.3% 39.8% 48.5% 47.4% 52.7% 49.6% 57.7% 62.3% 64.8% 59.8% 60.2% 66.6% -20.0%
MOV 4.9% 4.9% 6.7% 5.7% 8.5% 10.7% 9.2% 7.6% 8.2% 10.8% 10.1% 9.8% 9.9% -5.0%
Transit 7.5% 12.3% 8.3% 10.1% 9.7% 5.1% 9.8% 8.7% 7.7% 3.9% 5.8% 6.1% 4.0% 3.5%
School Bus 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.3% 0.0% 0.1% 0.2% 0.0% 0.0%
Bicycle* 30.0% 33.7% 35.3% 26.5% 23.3% 20.5% 21.2% 15.6% 9.9% 12.3% 12.4% 14.1% 10.6% 19.4%
Foot 10.9% 14.8% 10.0% 9.2% 11.1% 11.0% 10.3% 10.4% 11.8% 8.2% 11.8% 9.6% 8.9% 2.0%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of
Trips 383 749 910 754 1,021 1,101 951 1,161 947 1,192 1,146 1,111 1,302
Modes with shifts that are statistically significantly different between 1990 and 20 23 are shaded.
Modes with shifts that are statistically significant different between 2018 and 2023 are bolded.
* In 2023 included 1.8% corresponding to E-bike and E-scooter.
3 See page 32 for a description of how trips were categorized. Using the trip classification scheme displayed in Figure 52:
Types of Trips, the “home-based work” commute trips could be determined. Still, a small percentage of the work commute
would not be accounted for when a work trip was “linked,” that is, a trip where the person makes a stop on the way to or
from work. For example, if the participant stopped at the post office on the way to work, the first trip would be classified as
“home-based other” and the second trip would be categorized as “non-home based”. Neither of these legs of the trip would
be counted as the work commute. Similarly, if a participant drove to the Park-n-Ride, and then took a bus to work, neither
trip would be classified as “home-based work;” the first would be coded as “home-based other” the second as “non-home
based.” To be sure trips were identified as part of the work commute, another code was created which allowed the trips to
be distinguished as “linked”. All the linked trips are included in the analysis of “work commute” trips.
Modal Shift in the Boulder Valley: 1990-2023
Page 9
From 1990 to 2023 a decrease was observed in the proportion of miles traveled by driving alone for
the work commute. From 2012 to 2018 there has been a large decrease in the proportion of miles
traveled by driving alone for the work commute follow up by a large increase in 2023.
The initial decreases observed in the proportion of work commute miles traveled via SOV, and the
initial increases in transit miles may reflect the emphasis of GO Boulder’s programs. At the time of
GO Boulder’s inception, a great deal of emphasis was placed on the work commute. The Eco-Pass
program provided RTD bus passes to many employees in the Boulder Valley.
Over time additional emphases and programs were implemented to influence other mode uses. For
example, the modal shift of miles traveled by bicycle for the work commutes has increased about 8%
since 1990, with much of the change occurring between 2000 and 2003; and again from 2012 to
2015. This shift in bicycle travel (trip and miles) may be due to the addition of bike/pedestrian
underpasses and the continued progress in completing the facilities of the Bicycle System Plan.
Figure 14: Modal Split of Miles for the Work Commute, 1990-2023
Travel Mode
Percent of Work Commute Miles Change
1990 to
2023 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
SOV 66.9% 45.6% 56.9% 69.7% 59.7% 66.6% 63.6% 68.8% 66.7% 71.5% 66.6% 64.5% 71.9% -5.0%
MOV 9.0% 4.8% 6.7% 10.9% 9.1% 10.3% 12.8% 6.3% 11.2% 11.9% 14.9% 10.1% 10.9% -1.9%
Transit 10.1% 33.6% 20.6% 8.7% 19.5% 11.8% 12.6% 17.4% 16.2% 11.2% 12.7% 16.5% 11.2% -1.1%
School Bus 0.2% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.1% 0.0% 0.0% 0.6% 0.0% +0.2%
Bicycle* 12.4% 14.0% 14.6% 9.6% 10.6% 10.2% 10.0% 6.0% 4.4% 4.3% 4.6% 6.9% 4.7% +7.7%
Foot 1.4% 2.1% 1.3% 1.1% 1.1% 1.2% 1.0% 1.5% 1.3% 1.0% 1.2% 1.4% 1.3% +0.1%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of Work
Commute Miles 2,048 3,468 4,508 4,411 6,215 5,980 5,607 6,637 5,846 6,326 7,111 6,412 6,818
Modes with shifts that are statistically significantly different between 1990 and 2023 are shaded.
Modes with shifts that are statistically significant different between 2018 and 2023 are bolded.
* In 2023 included 0.7% corresponding to E-bike and E-scooter.
Modal Shift in the Boulder Valley: 1990-2023
Page 10
Figure 15 compares the change in Boulder’s modal split of the work commute to the national trends.
Use of a private vehicle for the work trips which had remained constant across the U.S., experienced
an increase in 2023, both measured in trips and miles; while Boulder which had experienced a decline
in work trips and miles traveled for the work commute made via private vehicles, showed a sharp
increase in 2023. The trend line for the proportion of work trips and miles made via transit has been
volatile in Boulder. Nationally, little change has been observed in transit use for work trips or miles,
although 2023 showed the lowest values since 1990.
Figure 15: Percent of Work Commute Trips and Miles: Boulder Compared to the U.S., 1990-2023
Figure 16 displays the work commute trips made on the assigned travel study day by study
participants’ workplace location. Those who worked in Boulder were least likely to have used an SOV
for any part of their work commute compared to those who worked in other cities. A greater
proportion of the work commute trips made by Boulder Valley residents who worked in Boulder
were made by bicycle or by foot.
Among travel diary study participants who worked in Boulder, about 8% of the trips made for the
work commute were made using transit. This represents a small decrease in transit use for the work
commute since 2018 (see Figure 17).
Bicycle use for the work commute was again very high among Boulder residents who worked in
Boulder, with 1 in 3 work commute trips reported as being made by bicycling. This represented about
a 20% gain since 1990.
51%
94%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%19901992199419961998200020022004200620082010201220142016201820202022Percent of Work Commute TripsBoulder: Personal Vehicles
U.S.: Personal Vehicles
Boulder: Transit
U.S.: Transit
76%
94%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%19901992199419961998200020022004200620082010201220142016201820202022Percent of Work Commute MilesBoulder: Personal Vehicles
U.S.: Personal Vehicles
Boulder: Transit
U.S.: Transit
Modal Shift in the Boulder Valley: 1990-2023
Page 11
Caution should be used when considering the modal split of Denver work trips as few work commute
trips captured on the diary day were made to Denver (N=24). While the response rate has decreased
over the study years and fewer trips have been captured, these trips continue to be weighted to
reflect the population and in Figure 17 we see that there has been a gradual trend toward more bike
and walking commute trips in Boulder.
Figure 16: Modal Split of Work Commute Trips by Location of Workplace, 2023
Travel Mode Location of Workplace
Boulder Denver Other
Single-Occupancy Vehicle 37.8% 64.8% 87.7%
Multiple-Occupancy Vehicle 3.5% 24.6% 1.7%
Transit 8.2% 10.6% 7.2%
Bicycle** 35.0% 0.0% 3.4%
Foot 15.6% 0.0% 0.0%
Total 100% 100% 100%
Number of Work Commute Trips 269 24 51
** In 2023 included 1.8% corresponding to E-bike and E-scooter.
Figure 17: Modal Split of Work Commute Trips for Boulder Residents Who Work in Boulder,
1990-2023
Travel Mode
Percent of Work Commute Trips for BV Residents Who Work in Boulder Change
1990 to
2023 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
SOV 37.8% 28.6% 32.5% 40.2% 41.5% 48.9% 44.0% 55.0% 59.7% 61.8% 58.3% 59.5% 65.9% -28.1%
MOV 3.5% 3.0% 6.0% 3.5% 5.7% 8.6% 7.1% 7.6% 8.3% 10.0% 11.1% 9.6% 9.7% -6.2%
Transit 8.2% 9.5% 6.0% 11.5% 7.6% 3.5% 7.7% 5.4% 6.3% 2.8% 3.6% 3.7% 2.4% 5.8%
School Bus 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.4% 0.0% 0.2% 0.0% 0.0% 0.0%
Bicycle** 35.0% 40.5% 43.7% 33.3% 30.4% 26.6% 27.8% 21.6% 13.4% 16.0% 16.1% 16.0% 12.5% 22.5%
Foot 15.6% 18.4% 11.9% 11.5% 14.8% 12.4% 13.4% 10.4% 11.9% 9.4% 10.7% 11.3% 9.6% 6.0%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of Work
Commute Trips 269 528 705 575 648 758 646 786 647 874 856 810 1,048
Modes with shifts that are statistically significantly different between 1990 and 2023 (±4%) are shaded.
Modes with shifts that are statistically significant different between 2018 and 2023 (±4%) are bolded.
** In 2023 included 1.8% corresponding to E-bike and E-scooter.
Modal Shift in the Boulder Valley: 1990-2023
Page 12
TELECOMMUTING
Respondents were asked whether they had telecommuted on the day assigned to them to record their
travel. Since this question was first asked in 1996 and until 2015, in most years just over 10% of the
respondents have said that they telecommuted on their assigned travel day. In 2023 that proportion
doubled to 25%.
Figure 18: Telecommuting on Assigned Travel Day, 1996-2023
Did you telecommute on
the day you completed
the travel diary?
Percent of Respondents
2023 2018 2015 2012 2009 2006 2003 2000 1998 1996
Yes 24.6% 12.6% 11.4% 10.8% 8.1% 12.0% 12.2% 10.4% 11.0% 13.6%
No 75.4% 87.4% 88.6% 89.2% 91.9% 88.0% 87.8% 89.6% 89.0% 86.4%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of Respondents 658 563 930 742 829 882 890 1,160 1,010 1,056
In 2023, the scale of how often workers telework was changed to give more granularity to the
answers. About 1 in 4 respondents said they telework every day while 2 in 4 said they do it at least
twice a week.
Figure 19: Teleworking Status4 2023
4 “On average, how often do you telework (work at home instead of going into the office)? Include only full days at home when
you did not travel to your workplace.”
25%
10%
11%
6%
10%
9%
7%
23%
0%10%20%30%
Never
Less than once per month
1 to 3 days per month
Once a week
2 times a week
3 times a week
4 times a week
5 times a week or more
Modal Shift in the Boulder Valley: 1990-2023
Page 13
The new scale was re-coded into the previous scale for comparative purposes. As seen in Figure 20
the proportion of respondents who never telework decreased from 56% in 2009 to 25% in 2023.
Most of that reduction happened between 2018 and 2023. Currently, 3 in 4 Boulder workers telework
at least occasionally.
Figure 20: Teleworking Status 2009-2023
On average, how often do you telework (work at home
instead of going into the office)? (Include only full days at
home when you did not travel to your workplace.)
Percent of Respondents
2023 2018 2015 2012 2009
Every work day (I always work from my home) 22.9% 12.0% 12.0% 12.7% 7.9%
1 to 4 times per week 31.8% 10.1% 9.9% 8.2% 9.5%
Once or twice a month 11.2% 15.5% 15.1% 8.9% 9.8%
Occasionally 9.5% 19.9% 15.7% 21.1% 17.2%
Never 24.7% 42.5% 47.3% 49.1% 55.7%
Total 100% 100% 100% 100% 100%
Number of Respondents 663 573 934 748 837
Modal Shift in the Boulder Valley: 1990-2023
Page 14
MODAL SPLIT OF UNIVERSITY/COLLEGE STUDENTS
The modal split for this group is traditionally quite different than the rest of Boulder’s population
due to the students’ high use of alternate modes. In all years, SOVs were used for about 20% to 30%
of all university students’ trips, and for 5% to 15% of the trips made to school. This low use may be
attributed to the lower vehicle availability of students (in 2023, 0.74 vehicles per driver for students
versus 0.88 vehicles per driver for non-students) and the scarcity and cost of parking on campus. It
may also be due to the fact that some students must park more than a block from school, and thus
recorded the purpose of the automobile portion of their trip as “change travel mode,” and the walk
from the car to school as “school”.
Figure 21: Modal Split of All Trips Made by University/College Students, 1990-2023
Travel Mode Percent of Trips Made by University / College Students Change
1990 to
2023 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
SOV 20.8% 28.2% 21.1% 19.6% 22.9% 19.1% 26.0% 22.3% 21.0% 17.0% 19.8% 20.6% 24.8% -4.0%
MOV 11.4% 17.0% 12.1% 9.6% 16.3% 17.0% 17.5% 13.3% 17.0% 19.2% 17.3% 19.3% 19.7% -8.3%
Transit 9.5% 8.9% 6.6% 10.3% 10.2% 10.8% 9.7% 10.1% 12.2% 6.2% 5.9% 4.7% 5.7% 3.8%
Bicycle** 25.8% 15.2% 34.5% 26.5% 22.9% 25.1% 15.5% 17.0% 11.3% 18.2% 19.2% 23.1% 17.6% 8.2%
Foot 32.5% 30.8% 25.7% 33.9% 27.7% 27.8% 31.4% 37.3% 38.5% 39.3% 37.8% 32.4% 34.2% -1.7%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of
Trips 753 699 1,230 1,168 1,140 1,072 1,747 1,696 1,400 1,379 1,572 1,734 1,901
No modes had statistically significant differences between 1990 and 2023.
Modes with shifts that are statistically significant different between 2018 and 2023 are bolded.
** In 2023 included 3.8% corresponding to E-bike and E-scooter.
Figure 22: Modal Split of School Commute Trips Made by University/College Students
Travel Mode
Percent of School Commute Trips Made by University/College Students Change
1990 to
2023 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
SOV 10.8% 4.4% 6.8% 4.5% 11.0% 5.2% 13.0% 8.7% 12.6% 5.7% 7.9% 8.8% 10.1% 0.7%
MOV 7.6% 5.4% 0.0% 1.9% 7.3% 1.2% 1.2% 3.6% 5.1% 3.0% 3.0% 1.7% 3.2% 4.4%
Transit 16.9% 18.1% 4.6% 16.8% 12.8% 19.9% 18.9% 10.4% 20.3% 8.0% 7.5% 8.5% 8.9% 8.0%
Bicycle 14.9% 29.7% 52.5% 33.0% 35.3% 42.9% 22.8% 22.7% 15.4% 30.9% 25.9% 31.5% 24.2% -9.3%
Foot 49.7% 42.4% 36.1% 43.8% 33.5% 30.8% 44.0% 54.6% 46.7% 52.4% 55.7% 49.5% 53.6% -3.9%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of School
Commute Trips 112 84 219 267 218 181 259 341 296 241 299 364 334
Modes with shifts that are statistically significant different between 1990 and 2023 are shaded.
Modes with shifts that are statistically significant different between 2018 and 2023 are bolded.
** In 2023 included 2.8% corresponding to E-bike and E-scooter.
Modal Shift in the Boulder Valley: 1990-2023
Page 15
TRIP CHARACTERISTICS
Summary Characteristics of All Trips
This section of the report explores the characteristics of the trips made by Boulder Valley residents.
Figure 23, below, displays summary trip characteristics for all trips, regardless of mode of travel.
These trip characteristics have remained fairly steady over the study period, although the average
number of miles traveled per day decreased slightly from 1990 to 2023.
On average, respondents traveled about 20 miles per day and made about 5 trips during the 24-hour
period assigned to them in 2023, with an average trip length of about 4 miles. Both the average trip
distance and the average trip time have slightly increased since 1990.
About 8% of respondents made no trips on their assigned travel day, an increase from the 4% who
did so in 1990, but similar to what has been observed in recent years.
Figure 23: Summary Trip Characteristics, All Trips, 1990-2023
Summary Travel
Characteristics
Year
Change
1990-
2023
2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Average number of trips
per day per person 5.1 5.3 5.4 4.9 5.1 5.7 5.5 6.1 5.9 6.2 6.1 6.0 5.9 -0.8
Average number of miles
per day per person 20.2 21.7 22.7 18.8 24.7 24.1 27.0 25.2 26.0 27.8 26.9 25.4 24.3 -4.1
Percent of people who
did not leave the house
on assigned travel day
7.6% 7.9% 5.7% 5.7% 5.8% 5.4% 5.2% 4.7% 4.9% 5.2% 4.1% 4.6% 4.1% 3.5%
Average estimated
trip length in miles5 4.3 4.3 4.4 3.8 5.0 4.3 5.1 4.3 4.3 4.7 4.5 4.6 4.0 0.3
Average estimated
trip time in minutes 18.4 19.4 19.6 15.8 17.0 16.0 15.4 13.5 11.4 13.3 11.8 14.9 14.4 4.0
Average miles per hour 14.0 13.6 13.8 13.8 15.7 15.7 16.0 15.4 15.5 15.2 15.9 15.7 15.1 -1.1
Characteristics with changes that are statistically significantly different between 1990 and 2023 are shaded.
Characteristics with changes that are statistically significant different between 2018 and 2023 are bolded.
5 Travel Diary Study participants are asked to record the estimated distance in miles or blocks of every trip they make. Thus,
trip distance is not measured objectively, but is determined by the respondents’ self-report. See Appendix E. Study
Methodology for a note on the adjustments made to these figures.
Modal Shift in the Boulder Valley: 1990-2023
Page 16
Trip Characteristics of the Work Commute
The travel characteristics of work commute trips are displayed in Figure 24. Figure 25 makes
comparisons to the national commute. The average work commute for Boulder residents was 5.5
miles in 2023, while the average work commute duration was about 20 minutes. As with all trips, the
work trips made by Boulder residents were shorter in length and duration than observed nationally.
Figure 24: Summary Work Commute Trip Characteristics, All Travel Modes, 1990-2023
Summary Travel
Characteristics
Year Change
1990-
2023 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Average estimated trip
length in miles 5.5 4.6 5.1 6.0 6.1 5.5 6.2 5.7 6.2 5.3 6.2 5.9 5.2 0.3
Average estimated trip
time in minutes 19.7 19.7 22.3 17.7 17.1 17.1 16.7 16.3 12.1 13.7 20.4 16.7 15.1 4.6
Average miles
per hour 15.5 13.5 14.4 17.1 18.3 17.8 18.6 17.9 18.6 18.1 18.9 19.6 18.4 -2.9
Characteristics with changes that are statistically significantly different between 1990 and 2023 are shaded.
Characteristics with changes that are statistically significant different between 2018 and 2023 are bolded.
Figure 25: Summary Work Commute Trip Characteristics, Boulder Compared to the U.S., 1990-
2023
Summary Travel
Characteristics
Boulder U.S. (NHTS*)
2023 2018 1990
Annual
Percent
Change
2022 2017 1990
Annual
Percent
Change
Average estimated
trip length in miles 5.5 4.6 5.2 +20% 13.65 11.46 10.65 +19%
Average estimated
trip time in minutes 19.7 19.7 15.1 +0% 27.75 26.58 19.60 +1%
* General commute patterns by mode of transportation.
2017 NHTS sample was address-based and among other changes included more urban and cell phone only households than
prior years.
Modal Shift in the Boulder Valley: 1990-2023
Page 17
A household travel survey that accompanied the diary asked respondents to identify where they
worked if they were employed. Since 2003, about three in four employed respondents work in
Boulder.
Figure 26: Location of Respondent’s Workplace, 1990-2023
Location of
Workplace
Percent of Respondents
2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Boulder 75.6% 78.5% 83.5% 80.6% 76.7% 73.2% 77.4% 62.9% 78.7% 81.7% 80.4% 81.5% 83.1%
Denver 7.8% 4.5% 6.0% 6.3% 6.2% 6.3% 6.2% 5.4% 8.7% 8.3% 8.3% 1.0% 8.3%
Longmont 1.6% 2.1% 2.0% 2.3% 3.4% 4.8% 3.8% 1.8% 2.5% 1.9% 1.8% 2.2% 1.2%
Broomfield 2.4% 3.3% 1.9% 4.1% 2.5% 3.9% 2.4% 2.2% 1.3% 2.5% 2.3% 3.3% 1.3%
Louisville 3.8% 2.4% 0.9% 0.8% 2.5% 3.0% 2.3% 2.0% 3.3% 2.2% 2.2% 0.5% 1.8%
Lafayette 1.5% 1.9% 0.8% 0.8% 1.8% 1.6% 1.0% 1.0% 0.6% 0.6% 1.7% 2.1% 0.7%
Other location 7.3% 7.3% 5.0% 5.1% 6.7% 7.1% 6.8% 24.6% 4.8% 2.9% 3.2% 9.5% 3.6%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of
Employed
Respondents
529 538 799 710 787 897 911 1,182 839 895 942 973 1,109
Modal Shift in the Boulder Valley: 1990-2023
Page 18
Automobile Trip Characteristics
Figure 27 and Figure 28 summarize the trip characteristics for automobile trips. The proportion of
respondents making at least one SOV trip on their assigned travel day has decreased from 65% in
1990 to 53% in 2023; the proportion making at least one MOV trip decreased from 48% in 1990 to
37% in 2023. On average, participants in the 2023 study made 1.7 SOV trips per day; those who made
at least one SOV trip made 3.3 trips on average. The average number of carpool trips per respondent
in 2023 was about 1.
The average trip distance was about 5 miles for SOV trips and about 7 miles for MOV trips. The
average trip duration in minutes was about 16 minutes for SOV trips, and about 18 minutes for MOV
trips.
Figure 27: Summary Trip Characteristics, SOV Trips, 1990-2023
Summary Travel Characteristics 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Average number of SOV trips
per day per person 1.74 1.80 1.75 1.65 1.80 2.03 2.00 2.36 2.28 2.41 2.37 2.34 2.49
Percent of people making
at least one SOV trip 53.4% 53.4% 48.1% 49.5% 53.6% 56.8% 56.6% 62.8% 59.5% 60.2% 63.0% 60.0% 64.6%
Average number of SOV trips per day
per person who made at least one SOV
trip
3.27 3.37 3.64 3.34 3.36 3.57 3.52 3.76 3.83 4.00 3.77 3.90 3.85
Average estimated trip length in miles 5.0 4.8 5.2 5.3 6.1 5.2 5.7 5.0 5.1 5.1 5.2 5.2 4.6
Average estimated trip time in minutes 15.8 18.2 17.2 15.8 16.3 14.6 13.3 11.5 9.6 12.6 11.4 13.7 12.9
Average miles per hour of SOV trips 18.5 17.6 18.2 19.5 21.1 20.3 21.0 19.7 20.0 19.4 20.5 20.2 19.3
Characteristics with changes that are statistically significantly different between 1990 and 2023 are shaded.
Characteristics with changes that are statistically significant different between 2018 and 2023 are bolded.
Figure 28: Summary Trip Characteristics, MOV Trips, 1990-2023
Summary Travel Characteristics 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Average number of MOV trips
per day per person 1.05 1.10 1.11 0.94 1.14 1.40 1.26 1.38 1.44 1.52 1.49 1.44 1.52
Percent of people making
at least one MOV trip 36.7% 37.4% 35.9% 32.4% 38.6% 43.3% 40.6% 43.1% 43.7% 46.9% 47.1% 44.2% 47.5%
Average number of MOV trips per day
per person who made at least one
MOV trip
2.87 2.94 3.09 2.90 2.95 3.23 3.10 3.20 3.30 3.23 3.16 3.26 3.19
Average estimated trip length in miles 7.0 7.0 7.8 6.0 7.5 6.2 8.6 6.4 6.1 7.5 6.8 6.6 5.8
Average estimated trip time in minutes 18.3 17.5 19.9 18.1 17.6 16.4 18.4 14.5 9.8 13.4 12.3 17.1 16.0
Average miles per hour of MOV trips 20.4 19.9 20.2 19.6 21.0 20.9 21.4 20.1 19.9 19.9 20.3 19.2 18.5
Characteristics with changes that are statistically significantly different between 1990 and 2023 are shaded.
Characteristics with changes that are statistically significant different between 2018 and 2023 are bolded.
Modal Shift in the Boulder Valley: 1990-2023
Page 19
Vehicle Miles Traveled per Capita
An estimate was created of per capita vehicle miles traveled (VMT) per adult Boulder Valley resident.
This estimate includes miles traveled in a single-occupancy vehicle and in a multiple occupancy
vehicle (this means that some of the MOV miles are “double-counted” because the miles traveled are
being assigned to all those in the vehicle.) There is some volatility in these estimates, because there
is a certain amount of error around each of the estimates that goes into the calculation. However, the
estimated number of vehicle miles traveled per capita has ranged for most of the time from about
5,000 to 7,500.
Figure 29: Vehicle Miles Traveled per Capita, 1990-2023
Calculating per capita VMT 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Average number of SOV trips
per day per person 1.74 1.80 1.75 1.65 1.80 2.03 2.00 2.36 2.28 2.41 2.37 2.34 2.49
Average estimated SOV trip length in
miles 5.0 4.8 5.2 5.3 6.1 5.2 5.7 5.0 5.1 5.1 5.2 5.2 4.6
Estimated SOV VMT per capita per day
(average number of trips x average trip
length)
8.70 8.64 9.10 8.75 10.98 10.56 11.40 11.80 11.63 12.29 12.32 12.17 11.45
Average number of MOV trips
per day per person 1.05 1.10 1.11 0.94 1.14 1.40 1.26 1.38 1.44 1.52 1.49 1.44 1.52
Average estimated MOV trip length in
miles 7.0 7.0 7.8 6.0 7.5 6.2 8.6 6.4 6.1 7.5 6.8 6.6 5.8
Estimated MOV VMT per capita per day
(average number of trips x average trip
length)
7.35 7.70 8.66 5.64 8.55 8.68 10.84 8.83 8.78 11.40 10.13 9.50 8.82
TOTAL VMT per capita per day
(SOV VMT + MOV VMT) 16.05 16.34 17.76 14.39 19.53 19.24 22.24 20.63 20.41 23.69 22.46 21.67 20.27
TOTAL annual VMT per capita per day
(assumes 48 weeks a year, 336 days) 5,393 5,490 5,967 4,833 6,562 6,463 7,471 6,932 6,858 7,960 7,545 7,282 6,811
Figure 30: Vehicle Miles Traveled per Capita taking into account vehicle occupancy of MOV
trips, 1990-2023
Calculating per capita VMT’ 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Estimated MOV VMT’ per capita per
day (average trip length divided the
average Vehicle Occupancy for Autos
with at Least Two Passengers)
3.10 2.81 3.35 2.55 3.01 2.54 3.52 2.61 2.47 3.10 2.80 2.66 2.35
TOTAL VMT’ per capita per day
(SOV VMT + MOV VMT’) 11.80 11.45 12.45 11.30 13.99 13.10 14.92 14.41 14.10 15.39 15.12 14.83 13.80
TOTAL annual VMT’ per capita per day
(assumes 48 weeks a year, 336 days) 3,964 3,848 4,182 3,798 4,701 4,402 5,015 4,843 4,737 5,171 5,080 4,983 4,636
Modal Shift in the Boulder Valley: 1990-2023
Page 20
Vehicle Occupancy
The average number of people in an automobile has not changed significantly from 1990 to 2023 (see
Figure 31). The average vehicle occupancy for all automobile trips was about 1.5 persons; for MOV
trips the average vehicle occupancy was about 2.3 persons. Just over 60% of all automobile trips were
made with only one person in the vehicle.
Figure 31: Vehicle Occupancy, 1990-2023
Number of
Occupants
Percent of Total Auto Trips
2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
1 62.7% 63.4% 63.1% 64.6% 61.5% 61.2% 63.7% 63.7% 62.0% 61.7% 61.0% 62.3% 62.6%
2 30.7% 25.3% 28.2% 26.9% 26.2% 27.9% 26.0% 25.6% 26.5% 27.4% 27.7% 26.4% 25.6%
3 4.0% 6.4% 6.1% 5.7% 7.0% 6.6% 6.7% 6.7% 6.7% 7.1% 7.3% 6.6% 7.6%
4 2.2% 4.0% 2.0% 2.1% 4.3% 3.1% 2.2% 3.2% 3.6% 3.2% 2.9% 3.4% 2.8%
5 or more 0.3% 0.9% 0.6% 0.7% 1.0% 1.2% 1.4% 0.9% 1.2% 0.8% 1.1% 1.4% 1.3%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Average Vehicle
Occupancy for all
Automobiles
1.47 1.54 1.44 1.45 1.55 1.54 1.48 1.51 1.54 1.54 1.56 1.56 1.55
Average Vehicle
Occupancy for
Autos with at Least
Two Passengers
2.26 2.49 2.33 2.35 2.49 2.44 2.44 2.45 2.47 2.42 2.43 2.48 2.47
Number of Trips 2,613 2,369 3,355 2,640 3,326 3,822 4,425 4,397 3,892 4,251 4,358 4,414 5,086
Modal Shift in the Boulder Valley: 1990-2023
Page 21
Vehicle Ownership and Availability
Vehicle availability and ownership for all study years are shown in Figure 32. Vehicle availability has
declined slightly since 1990, when the average was 1.0 vehicle for every household member aged 16
and over to 0.85 vehicles per household member aged 16 and older in 2023. The average number of
motorized vehicles per household has also declined, from 1.83 vehicles per household in 1990 to 1.55
vehicles per household in 2023. Bicycles per household has remained stable while in 2023 e-scooter
availability was asked for first time.
Figure 32: Vehicle Availability, Vehicles per Household 1990-2023
Vehicle and Bicycle Availability 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Average vehicle availability
(per person in household 16 or older) 0.85 0.90 0.89 0.89 0.93 0.90 0.89 0.96 0.92 0.89 0.99 0.98 1.00
Average number of motorized
vehicles per household 1.55 1.61 1.77 1.59 1.66 1.60 1.69 1.79 1.73 1.63 1.78 1.83 1.83
Average number of bicycles
per household 2.05 2.59 2.78 2.48 2.26 2.19 2.21 2.09 2.04 2.00 2.00 1.98 not
asked
Average number of e-bikes
per household .17 .04 not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
Average number of e-scooters
per household .02 not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
not
asked
About 1 in 4 residents said they never bike, while 3 in 4 residents said the same about e-bikes. Also,
9 in 10 respondents said they never use E-scooters (Figure 33). For biking, users mainly use private
bikes, while e-bikes and e-scooters are mostly accessed through apps or memberships (Figure 34).
Figure 33: Bicycles, E-bikes and E-scooters frequency of use, 2023
91%
6%
2%
0%
1%
0%
0%
1%
76%
6%
4%
4%
2%
2%
2%
5%
26%
16%
12%
8%
6%
8%
6%
18%
0%10%20%30%40%50%60%70%80%90%100%
Never
Less than once per month
1 to 3 days per month
Once a week
2 times a week
3 times a week
4 times a week
5 times a week or more
Bike
E-bike
E-scooter
Modal Shift in the Boulder Valley: 1990-2023
Page 22
Figure 34: Type of Bicycle, E-bike and E-scooter used, 2023
89%
10%
1%
75%
15%
12%
25%
1%
74%
0%10%20%30%40%50%60%70%80%90%100%
Neither
App/ membership
Private
Bike
E-bike
E-scooter
Modal Shift in the Boulder Valley: 1990-2023
Page 23
Transit Trip Characteristics
The characteristics of trips made on the assigned travel day via transit are shown in Figure 35. The
proportion of people who made at least one trip on the bus increased from about 5% in 1990 to about
10% in 2023. The average bus trip was about 8 miles. The estimated trip duration was 27 minutes.
Figure 35: Summary Trip Characteristics, Transit Trips, 1990-2023
Summary Travel Characteristics 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Average number of bus trips
per day per person 0.19 0.25 0.19 0.22 0.26 0.21 0.24 0.25 0.25 0.17 0.17 0.13 0.09
Percent of people making
at least one bus trip 9.6% 12.8% 10.7% 11.0% 12.5% 9.2% 11.2% 11.5% 10.3% 8.6% 7.7% 6.0% 4.8%
Average number of bus trips per day
per person who made at least 1bus trip 1.95 1.98 1.80 2.02 2.06 2.29 2.12 2.18 2.44 1.96 2.18 2.10 1.85
Average estimated trip length in miles 7.8 8.8 9.5 5.5 6.5 6.2 6.4 6.6 7.2 9.7 10.1 13.2 10.4
Average estimated trip time in minutes 26.5 27.1 29.0 21.8 16.4 21.1 21.2 16.6 18.1 18.4 28.3 29.7 29.7
Average miles per hour of transit trips 14.5 15.6 15.3 13.5 15.6 15.6 15.5 14.9 17.1 17.9 18.1 24.5 18.9
Characteristics with changes that are statistically significantly different between 1990 and 2023 are shaded.
Eco-Pass Status
In previous implementations of the travel diary, study participants were asked whether they had an
Eco-Pass, and what kind they held. Starting in 2009, participants were first asked if they were eligible
to have an Eco-Pass. About half of respondents said they were eligible for an Eco-Pass in 2023 (see
Figure 36). However, 7% of those eligible for a pass in 2023 had not picked up or activated their pass
(see Figure 37).
Figure 36: Eco-Pass Eligibility, 2009-2023
Are you eligible to have an Eco-Pass, an annual pass that
allows you unlimited bus rides? 2023 2018 2015 2012 2009
Yes, through my employer 17.0% 24.4% 21.8% 20.2% 17.6%
Yes, through my neighborhood 12.2% 13.2% 10.2% 11.4% 12.0%
Yes, a CU Boulder student Buff One pass 15.6% 15.8% 20.3% 20.2% 18.0%
Yes, CU Boulder faculty/staff Buff One pass 4.0% 4.5% 5.4% 5.2% 7.1%
Yes, other pass 1.2% 1.0% 0.9% 1.6% 1.7%
No, I am not eligible for an Eco-Pass 52.4% 46.3% 45.2% 46.1% 47.6%
Number of Respondents 892 765 1,117 1,036 1,112
* Percents may add to more than 100% as respondents could give more than one answer.
Figure 37: Eco-Pass Pick-up Status, 2009-2023
Did you pick up a pass (or passes)?* ** 2023 2018 2015 2012 2009
Yes 91.5% 79.3% 88.2% 79.7% 82.8%
No 8.5% 20.7% 11.8% 20.3% 17.2%
Total 100% 100% 100% 100% 100%
Number of Respondents 445 412 620 561 588
* Only asked of those eligible for an Eco-Pass.
** In 2023 this question was not asked. Instead, an option “haven’t picked-up or activated the pass” was offered while
inquiring about the frequency of Eco-Pass use. Both questions were re-coded for comparative purposes.
Modal Shift in the Boulder Valley: 1990-2023
Page 24
To compare Eco-Pass possession over time, those who were eligible for an Eco-Pass and reported
that they had picked one up were considered to have an Eco-Pass. As shown in Figure 38, about 43%
of study participants in 2023 held an Eco-Pass, a proportion that has been similar over the years. In
2023, about 19% of respondents had an Eco-Pass through their employer (including a university
faculty/staff transit pass), while 15% had a university student transit pass. Finally, about 9% held an
Eco-Pass through their neighborhood.
Figure 38: Eco-Pass Status, 1998-2023
Do you have an Eco-Pass? 2023† 2018† 2015† 2012† 2009† 2006 2003 2000 1998
No 56.7% 57.4% 51.4% 56.9% 56.4% 61.9% 53.9% 60.7% 61.0%
Yes, through employer 14.7% 16.9% 15.9% 13.1% 12.4% 12.3% 12.6% 11.2% 10.2%
Yes, a university faculty/staff transit pass 4.0% 4.1% 5.3% 4.7% 6.5% 3.7% 4.6% 2.9% 4.2%
Yes, a university student transit pass 14.9% 13.2% 19.8% 17.2% 15.4% 15.9% 23.2% 20.4% 21.2%
Yes, through neighborhood 8.9% 7.8% 7.0% 6.9% 8.1% 4.7% 2.6% 3.9% 3.5%
Yes, other pass 0.7% 0.6% 0.6% 1.2% 1.2% 1.4% 3.1% 0.9% 0.0%
Total 100 100% 100% 100% 100% 100% 100% 100% 100%
Number of Respondents 883 766 1122 1040 1118 1,154 1,278 1,191 1,035
†This percent is an estimate, based on respondent’s Eco-Pass eligibility and pick-up status. Since the question asked in 1998
through 2006 was changed in 2009, results prior 2009 may not be directly comparable to those of 2009 and later.
Beginning in 2009, survey participants with an Eco-Pass were asked how often, on average, they used
their Eco-Pass. About two in three of those with an Eco-Pass used it at least once a month during
2023.
Figure 39: Use of the Eco-Pass, 2009-2023
About how often, on average, do you use your
Eco-Pass?* 2023 2018 2015 2012 2009
More than once a week 22.1% 32.6% 31.2% 33.0% 41.4%
About once a week 10.8% 12.5% 11.1% 11.8% 15.4%
About once every two weeks 10.8% 16.1% 16.8% 15.1% 10.2%
About once a month 20.2% 19.2% 16.7% 17.8% 10.7%
Less often than once a month 27.0% 19.6% 24.3% 22.3% 22.3%
Haven’t used 9.1% - - - -
Total 100% 100% 100% 100% 100%
Number of Respondents 407 345 552 449 488
* Only asked of who have an Eco-Pass.
** The option “Haven’t used” was added in 2023.
Modal Shift in the Boulder Valley: 1990-2023
Page 25
Bus ridership has been positively associated with having an Eco-Pass. Since 1998, between 3% and
6% of non-Eco-Pass holders made at least one bus trip compared to 17% to 26% of Eco-Pass holders
(Figure 40).
Figure 40: Bus Ridership by Eco-Pass Status: Percent Who Made at Least 1 Trip on the Bus.
1998-2023
19.6%
22.9%
20.3%19.4%
22.3%
19.4%
17.9%
25.5%
17.2%
4.6%3.8%3.5%3.2%
5.7%5.1%3.7%4.1%4.2%
0%
10%
20%
30%
1998 2000 2003 2006 2009 2012 2015 2018 2023Percent of RespondentsHas Eco-Pass Does Not Have Eco-Pass
Modal Shift in the Boulder Valley: 1990-2023
Page 26
Non-Vehicle Trip Characteristics: Walking and Biking
In all study years about a third of respondents made at least one walking trip on their assigned travel
day (see Figure 41). Walking trips have tended to be quite short in distance; the average trip length
was 0.8 miles in 2023.
Figure 41: Summary Trip Characteristics, Pedestrian Trips, 1990-2023
Summary Travel
Characteristics 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Average number of pedestrian
trips per day per person 1.01 1.03 0.90 0.92 0.86 0.99 0.98 1.15 1.21 1.21 1.11 0.97 1.04
Percent of people making at least
one pedestrian trip 37.5% 36.8% 34.3% 30.8% 33.0% 34.6% 34.8% 36.9% 39.1% 39.9% 36.9% 34.8% 33.0%
Average number of pedestrian
trips per day per person who
made at least one pedestrian trip
2.69 2.80 2.61 2.99 2.62 2.85 2.81 3.11 3.09 3.04 3.00 2.78 3.16
Average estimated pedestrian
trip length in miles 0.8 0.8 0.8 0.7 0.7 0.9 0.9 0.7 0.8 0.7 0.7 0.7 0.7
Average estimated pedestrian
trip time in minutes 19.4 19.4 17.4 13.2 14.9 17.3 13.6 14.8 15.3 15.1 15.1 13.6 14.4
Average miles per hour of
pedestrian trips 3.4 3.5 3.3 3.7 3.2 3.6 3.9 2.8 3.5 3.3 3.6 3.4 3.3
The proportion of respondents making one or more trips by bicycle on their assigned travel day
increased from 15% in 1990 to 21% in 2023 (see Figure 42). In 2023 the average distance of a bike
trip was about 2.6 miles and took about 20 minutes to complete.
Figure 42: Summary Trip Characteristics, Bicycle Trips, 1990-2023
Summary Travel
Characteristics 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Average number of bicycle trips
per day per person 0.60 0.82 0.97 0.84 0.72 0.70 0.70 0.55 0.45 0.52 0.65 0.66 0.50
Percent of people making at least
one bicycle trip 21.3% 27.0% 32.7% 25.2% 23.9% 20.4% 23.2% 17.1% 15.0% 16.6% 19.8% 20.9% 15.2%
Average number of bicycle trips
per day per person who made at
least one bike trip
2.84 3.05 2.95 3.31 3.01 3.44 3.02 3.24 3.00 3.16 3.28 3.14 3.28
Average estimated bicycle trip
length in miles 2.6 2.3 1.8 1.9 2.5 2.2 2.8 2.0 2.4 2.2 2.3 2.0 2.1
Average estimated bicycle trip
time in minutes 20.5 22.4 23.5 14.6 18.3 16.3 16.9 15.4 13.6 14.3 9.5 14.1 15.1
Average miles per hour 8.5 8.0 7.7 7.8 8.1 8.1 8.8 8.2 8.7 8.4 8.4 7.7 8.2
Characteristics with changes that are statistically significantly different between 1990 and 2018 are shaded.
Characteristics with changes that are statistically significant different between 2018 and 2018 are bolded.
Modal Shift in the Boulder Valley: 1990-2023
Page 27
In 2023, the Travel Diary incorporated trips made by E-Bike and E-scooter for the first time. As seen
in Figure 43, nearly 5% of respondents reported making one or more trips by e-bike on their
designated travel day, whereas the proportion of respondents using e-scooters was below 1%. It's
important to interpret the characteristics of E-scooter rides cautiously due to the limited number of
respondents recording such trips in their travel diaries.
Figure 43: Summary Trip Characteristics, E-bike and E-scooter Trips, 2023
Summary Travel Characteristics E-bike E-scooter
Average number of trips per day per person 0.19 0.01
Percent of people making at least one trip 5.6% 0.5%
Average number of trips per day per person who made at least one trip 3.46 1.52
Average estimated trip length in miles 1.6 5.5
Average estimated trip time in minutes 16.8 16.5
Average miles per hour 7.7 18.4
Modal Shift in the Boulder Valley: 1990-2023
Page 28
Trip Distance
In Figure 44, trip distances are exhibited by mode of travel. For motorized vehicle trips, private
vehicle and transit trips distances tend to be either middle distance, between one and two-and-a-half
miles, or over a longer length (20 or more miles). These “peaks” are even more evident for bus trips
than for drive alone or carpool trips. Bike and walking trips, on the other hand, tend to be much
shorter, especially for walking trips.
Figure 44: Trip Distance by Mode of Travel, 2023
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%0 - 0.490.5 - 0.991.00 - 2.492.50 - 4.995.00 - 9.9910.00 - 14.9915.00 - 19.9920.00+Percent of TripsDistance in Miles
Private
vehicle
trips
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%0 - 0.490.5 - 0.991.00 - 2.492.50 - 4.995.00 - 9.9910.00 - 14.9915.00 - 19.9920.00+Percent of TripsDistance in Miles
Transit
trips
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%0 - 0.490.5 - 0.991.00 - 2.492.50 - 4.995.00 - 9.9910.00 - 14.9915.00 - 19.9920.00+Percent of TripsDistance in Miles
Pedestrian
trips
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%0 - 0.490.5 - 0.991.00 - 2.492.50 - 4.995.00 - 9.9910.00 - 14.9915.00 - 19.9920.00+Percent of TripsDistance in Miles
Bicycle
trips
Modal Shift in the Boulder Valley: 1990-2023
Page 29
Trip Start Times
Trip start and end times were recorded by respondents as they kept track of their travel throughout
their assigned travel day. The graph in Figure 45 shows when travel activity took place. Most travel
occurred between 6:00 am and 8:00 pm, with a large spike during the afternoon commute time
(about 4:00 pm to 6:00 pm), and smaller peaks for the morning commute time and the noontime
lunch hour.
Figure 45: Time When Trip Began, 2018-2023
0%
2%
4%
6%
8%
10%
12%Percent of TripsTrip start time
2018 2023
Modal Shift in the Boulder Valley: 1990-2023
Page 30
Deliveries to the Home or Office
Beginning in 1998, study participants were asked about certain behaviors which might replace trips.
They were asked whether they had any goods or services delivered to their work or home and
whether they had telecommuted on their assigned travel day (see page 12 for information on
telecommuting).
About 8% of respondents in 1998 had received at least one delivery on their assigned travel day, and
about 20% received a delivery in 2023 (see Figure 46). About one-third of the respondents who
received a delivery in 2023 felt that the delivery took the place of a travel trip they might have made
to seek the good or service (see Figure 47).
As simple calculation (the percent of those who received a delivery times the percentage of deliveries
that replace a trip) shows that 7.6% of respondents received a delivery that substituted for travel in
2023, compared to about 2.5% in the previous 20 years (see las row in Figure 47).
Figure 46: Deliveries Received by Respondents, 1998-2023
Percent of Respondents Who Received
Any Deliveries On Their Assigned Travel
Day
2023 2018 2015 2012 2009 2006 2003 2000 1998
No, did not receive deliveries 79.8% 89.1% 90.4% 93.7% 94.9% 93.6% 93.8% 94.6% 92.1%
Yes, received deliveries 20.2% 10.9% 9.6% 6.3% 5.1% 6.4% 6.2% 5.4% 7.9%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of respondents 900 762 1,109 1,036 1,107 1,130 1,262 1,150 1,008
Figure 47: Did Deliveries Replace Any Drive Alone Trips, 2000-2023
Did the delivery substitute for a travel
trip you might have made to seek the
good or service?*
2023 2018 2015 2012 2009 2006 2003 2000
Yes 37.5% 22.1% 51.0% 36.4% 46.3% 41.8% 43.7% 44.2%
No 62.5% 77.9% 49.0% 63.6% 53.7% 58.2% 56.3% 55.8%
Total 100% 100% 100% 100% 100% 100% 100% 100%
Number of respondents 178 84 104 67 54 72 81 97
Percent of respondent who had a
delivery that replaced a travel trip 7.6% 2.4% 4.9% 2.3% 2.4% 2.7% 2.7% NA
*Question only asked of those who had received deliveries.
Modal Shift in the Boulder Valley: 1990-2023
Page 31
PURPOSE OF TRAVEL
In addition to recording information about the time of day and mode of transportation used for each
trip, respondents were also asked to document the purpose of each trip they made. Figure 48 and
Figure 49 show the reasons for travel by trips made and by miles traveled, respectively. Patterns of
trip purpose were fairly similar over the entire study period. Aside from the “go home” trips (about
a third of all trips and miles) and work-related trips (11% of trips and 12% of miles), recreational
trips account for one of the largest proportion of trip purposes; 20% of trips and 26% of miles in
2023. These figures represent the highest values since the inception of the study.
Figure 48: Purpose of Trips, 1990-2023
Trip Purpose 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Go Home 34.5% 34.2% 35.0% 34.7% 33.7% 33.1% 33.3% 33.7% 32.0% 31.6% 32.8% 32.3% 33.6% Work All 10.5% 13.3% 14.3% 13.8% 13.9% 13.9% 13.2% 13.1% 13.1% 15.5% 14.4% 14.1% 15.1%
Work Commute 9.0% 7.7% 8.8% 9.2% 8.6% 8.5% 9.2% 9.0% 8.8% - - - -
Other Work/Business 1.5% 5.6% 5.5% 4.6% 5.3% 5.4% 4.0% 4.1% 4.3% - - - -
Social/Recreation 19.8% 17.0% 16.4% 13.4% 16.2% 14.8% 16.2% 12.9% 14.4% 13.9% 13.5% 12.6% 12.3%
Shopping 12.4% 11.1% 9.6% 11.1% 10.3% 11.5% 10.8% 11.0% 10.2% 11.3% 10.6% 11.7% 11.0%
Personal Business 5.8% 6.5% 7.3% 6.3% 6.5% 8.6% 8.1% 8.7% 9.5% 10.1% 9.4% 11.1% 11.9%
School 3.1% 3.0% 4.7% 6.3% 4.6% 3.8% 5.5% 5.5% 6.0% 4.6% 5.4% 6.5% 5.6%
Eat a Meal 4.8% 4.7% 5.6% 7.1% 6.3% 5.4% 5.0% 5.3% 5.9% 6.1% 3.5% 5.4% 4.6%
Drive a Passenger 3.5% 3.8% 3.5% 4.8% 3.9% 4.7% 4.5% 5.0% 4.7% 4.3% 4.4% 3.8% 4.0%
Change Travel Mode 2.4% 6.3% 3.1% 2.5% 4.2% 3.5% 3.1% 4.8% 4.2% 2.7% 5.4% 2.0% 1.7%
Other 3.1% 0.1% 0.4% 0.0% 0.4% 0.7% 0.2% 0.0% 0.1% 0.0% 0.5% 0.6% 0.1%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of trips 4,620 4,088 5,762 4,831 5,496 6,076 6,373 6,773 5,981 6,446 6,711 6,672 7,350
Figure 49: Purpose of Trips Miles, 1990-2023
Trip Purpose 2023 2018 2015 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990
Go Home 33.3% 36.6% 35.7% 35.4% 34.3% 35.5% 30.3% 32.5% 31.7% 32.1% 32.7% 33.8% 34.3% Work All 12.0% 12.4% 16.4% 18.6% 15.6% 15.6% 15.6% 18.3% 18.10% 16.6% 19.2% 18.1% 18.1%
Work Commute 9.8% 8.5% 10.0% 14.9% 10.7% 11.1% 11.0% 11.8% 10.5% - - - -
Other Work/Business 2.2% 3.9% 6.4% 3.7% 4.9% 4.5% 3.80% 7.3% 7.6% - - - -
Social/Recreation 25.8% 20.7% 19.9% 15.0% 21.4% 15.2% 25.8% 16.4% 18.3% 18.6% 17.9% 18.1% 16.8%
Shopping 7.9% 6.1% 6.3% 8.4% 6.9% 8.5% 7.0% 8.7% 6.6% 7.0% 5.7% 7.3% 7.8%
Personal Business 5.6% 7.4% 6.8% 5.7% 6.3% 7.6% 7.5% 6.9% 7.5% 10.2% 7.9% 8.4% 11.1%
School 2.2% 1.0% 1.3% 3.4% 1.6% 2.6% 2.8% 1.8% 2.8% 1.6% 2.4% 3.1% 2.5%
Eat a Meal 3.7% 3.1% 4.5% 4.0% 3.1% 4.2% 2.8% 3.4% 3.3% 3.6% 5.9% 3.4% 2.7%
Drive a Passenger 4.2% 4.3% 5.0% 6.6% 5.4% 5.5% 4.7% 5.6% 5.8% 6.2% 4.8% 3.8% 3.8%
Change Travel Mode 2.2% 8.2% 3.7% 2.7% 5.0% 4.2% 3.4% 6.4% 5.9% 4.2% 3.1% 3.4% 3.0%
Other 3.2% 0.1% 0.4% 0.0% 0.4% 1.1% 0.1% 0.0% 0.1% 0.0% 0.4% 0.5% 0.1%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Number of trips 18,649 17,405 25,303 18,251 26,983 25,742 31,195 28,657 25,538 30,033 30,282 29,710 29,587
Modal Shift in the Boulder Valley: 1990-2023
Page 32
Trip purpose by travel mode is shown in Figure 50, while Figure 51 displays the modal split of trips
by the trip purpose. The types of trips most likely to have been made by driving alone in 2023 were
shopping trips, recreation trips and work-related trips. The trips most likely to be made by transit
were work, school and “change travel mode”. Work commute was a popular choice for traveling by
bicycle while ‘social/recreation’ was a popular choice for traveling by foot.
Figure 50: Purpose of Trips by Travel Mode, 2023
Trip Purpose
Percent of Trips by Travel Mode
Single-
Occupancy
Vehicle
Multiple-
Occupancy
Vehicle
Transit Bicycle Foot
Go home 36.8% 35.4% 28.7% 35.1% 30.5%
Shopping 15.9% 13.7% 5.9% 10.5% 8.3%
Social/recreation 13.0% 20.3% 10.5% 19.1% 32.0%
Personal business 8.8% 4.0% 3.8% 5.9% 3.2%
Work or work commute 10.2% 2.7% 20.8% 15.6% 6.0%
Other work/business 2.0% 0.8% 1.9% 2.2% 1.0%
Eat a meal 4.2% 8.2% 0.6% 2.9% 4.8%
Drive a passenger 2.5% 10.4% 0.0% 2.1% 0.2%
Change travel mode 0.5% 0.6% 13.9% 2.5% 5.0%
School 1.1% 1.7% 13.0% 2.8% 6.4%
Other 5.0% 2.3% 0.8% 1.2% 2.7%
Total 100% 100% 100% 100% 100%
Number of trips 1,617 1,001 184 815 997
Figure 51: Modal Split of All Trips by Trip Purpose, 2023
Modal Split of All Trips
Percent of Trips by Trip Purpose go home personal business shopping School work or work commute other work/business social/ recreation change travel mode drive a passenger eat a meal SOV 37.3% 53.0% 44.8% 12.6% 39.6% 45.3% 23.1% 6.9% 24.6% 30.2%
MOV with adults 15.0% 11.0% 19.9% 0.0% 4.0% 8.3% 17.3% 5.9% 24.5% 32.0%
MOV with children 7.2% 3.7% 4.0% 11.5% 2.4% 2.4% 5.0% 0.0% 39.0% 5.1%
Transit 3.3% 2.6% 1.9% 16.5% 9.2% 4.9% 2.1% 23.3% 0.0% 0.5%
Bicycle* 18.0% 18.0% 15.0% 15.9% 30.6% 25.3% 17.1% 18.8% 10.6% 10.5%
Foot 19.1% 11.7% 14.5% 43.6% 14.2% 13.8% 34.9% 45.2% 1.4% 21.7%
Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
1,594 269 573 145 417 72 913 109 163 222
* It also includes E-bike and E-scooter.
Modal Shift in the Boulder Valley: 1990-2023
Page 33
Traditional transportation planning has often focused on origins and destinations of trips,
particularly those based at home or work. Thus, trips have often been classified in more aggregated
categories of purpose depicting “home-based work” trips, “home-based other” trips and “non-home”
trips. The following figure describes the classification scheme.6
Figure 52: Types of Trips
Boulder residents’ trips were categorized using this model. The proportion of trips made with origins
and destinations of “home-work”, “home-other” and “non-home” was similar for all study years. Most
trips were made between respondents’ homes and a destination other than work. One in four trips
neither began nor ended at home. About 8% of trips were direct travel between work and home.
Figure 53: Types of Trips Made, 2023
6 This coding scheme was taken from the Puget Sound Council of Governments Travel Study, 1985. Some small alterations
were made to the scheme.
Home-based
Other, 66%Home-based
Work, 8%
Non-Home-
based, 26%
Home-based Work:
Trips from home to work
or work to home
with no stops
along the way
Non-Home-based:
Trips that have neither origin nor destination at home
Home-based Other:
Trips from home to
someplace other than
work or to home from
someplace other
than work
Modal Shift in the Boulder Valley: 1990-2023
Page 34
The typology of trips by travel mode used is presented in Figure 54, while Figure 55 shows the modal
split of all trips by the trip type category. Among all modes, home-other trips were the most common,
except for the transit trips, which were often non-home based (likely due to the use of another mode
to get to or from the bus).
Figure 54: Type of Trips by Mode of Trip, 2023
Trip Type
Percent of Trips by Travel Mode
Single-
Occupancy
Vehicle
Multiple-
Occupancy
Vehicle
Transit Bicycle Foot
Home-based Other 65.6% 72.1% 32.9% 64.2% 68.8%
Home-based Work 10.0% 1.5% 15.7% 13.0% 4.2%
Non-home Based 24.4% 26.4% 51.4% 22.8% 27.0%
Total 100% 100% 100% 100% 100%
Number of trips 1,620 1,002 184 816 995
Figure 55: Modal Split of All Trips by Type of Trip, 2023
Modal Split of All Trips Percent of Trips by Type of Trip
Home-based Other Home-based Work Non-home Based
SOV 34.8% 45.7% 32.6%
MOV with adults 15.9% 1.9% 16.8%
MOV with children 7.7% 2.4% 5.0%
Transit 2.0% 8.1% 7.8%
Bicycle 17.2% 29.8% 15.3%
Foot 22.4% 11.7% 22.2%
Total 100% 100% 100%
Number of trips 3,053 355 1,214
Modal Shift in the Boulder Valley: 1990-2023
Page 35
Appendix A. National Travel Data
This appendix contains data from other sources about travel behavior in the nation as whole, to
which the travel behavior of Boulder Valley residents can be compared. The data sources included
are the National Household Transportation Survey and the U.S. Census.
The National Household Transportation Survey (NHTS, formerly the National Personal
Transportation Study (NPTS)), commissioned by the U.S. Department of Transportation, is a study of
the travel patterns of the nation as a whole using a diary methodology similar to the one used in this
research project.
The NHTS was conducted previously in 2001, 2009, 2017 and 2022 and the NPTS in 1995, 1990,
1983, 1977 and 1969. Comparisons are made in this report between the 1990 NPTS and the 2022
NHTS to the Boulder Travel Diary Study of 1990 and 2023 so that the time periods between the
national study and the Boulder study largely overlap. This way, comparisons can be made between
temporal trends and point-in-time observations, to understand how Boulder’s travel patterns may
differ from those seen nationally.
In general, Boulder Valley residents made more trips per day compared to the U.S. population. The
average trip distance of Boulder Valley residents was about a third of that observed among residents
in the nation. Work commute distances were also much shorter for Boulder residents compared to
U.S. residents, but the duration of the work commute was only somewhat shorter. The number of
personal vehicles per household decreased among Boulder residents from 1.83 in 1990 to 1.55 in
2023, while it increased slightly among U.S. residents.
Figure 56: Household and Travel Characteristics, Boulder Compared to the U.S.
Characteristic Boulder U.S. NHTS/NPTS*
2023 2018 2009 2000 1990 20221 2017 2009 2001 1990
Average number of trips 5.1 5.3 5.1 6.1 5.9 2.08 3.37 3.79 3.74 3.76
Average trip distance, all trips 4.3 4.3 5.0 4.3 4.0 12.54 10.70 9.75 10.04 9.47
Average work-related trip distance 5.5 4.6 6.1 5.7 5.2 13.65 11.46 11.79 12.11 10.65
Average work-related trip duration 19.7 19.7 17.1 16.3 15.1 27.75 26.58 23.85 23.32 19.60
Personal vehicles per household 1.55 1.61 1.66 1.79 1.83 1.81 1.88 1.86 1.89 1.77
*Daily trip rates and person miles of travel per person, general commute patterns by mode of transportation and major travel
indicators.
2017 NHTS sample was address-based and among other changes included more urban and cell phone only households than
prior years. This and other methods changes in the data series are outlined in the 2017 NHTS report.
1 Federal Highway Administration. (2022). 2022 NextGen National Household Travel Survey Core Data, U.S. Department of
Transportation, Washington, DC. Available online: http://nhts.ornl.gov.
Modal Shift in the Boulder Valley: 1990-2023
Page 36
Over the period of 1990 to 2023, the proportion of trips made by Boulder Valley residents in a
private vehicle have decreased from 70.5% to 56.8%, an average annual decrease of 0.41%. In
the U.S. as a whole, the proportion of trips made in a private vehicle stayed mostly unchanged
from 1990 to 2022.
Figure 57: Modal Split of All Trips, Boulder Compared to the U.S.
Travel Mode Boulder U.S. NHTS/NPTS*
2023 2009 1990 2022 2009 1990
SOV 35.1% 56.8% 37.1% 60.8% 44.2% 70.5% 87.3% 83.4% 87.7% MOV 21.7% 23.7% 26.3%
Public Transportation/ Transit 4.0% 5.4% 1.6% 1.5% 1.9% 1.8%
Walk 21.6% 17.9% 18.2% 6.8% 10.4% 7.2%
School Bus 0.0% 17.7% 0.1% 16.0% 0.6% 9.9% 4.4% 4.2% 3.3% Bike 17.7% 15.9% 9.1%
Total 100% 100% 100% 100% 100% 100%
*Percent of person trips by mode of transportation.
2017 NHTS sample was address-based and among other changes included more urban and cell phone only households than
prior years.
The proportion of miles traveled by private vehicle was lower in Boulder than in the nation as a whole
(see Figure 58). Miles traveled by public transit was higher among Boulder residents compared to
national residents in 1990, and increased significantly in Boulder over the time period, while
remaining relatively stable in the nation.
Figure 58: Modal Split of All Miles, Boulder Compared to the U.S.
Travel Mode Boulder U.S. NHTS/NPTS*
2023 2009 1990 2022 2009 1990
SOV 41.8% 77.9% 46.1% 82.0% 50.0% 87.7% 83.1% 88.3% 88.4% MOV 36.1% 35.9% 37.7%
Public Transportation/Transit 7.6% 6.9% 4.1% 1.2% 1.5% 2.1%
Walk 4.1%
14.5%
2.5%
11.1%
3.0%
8.1% 15.7% 10.2% 9.5% School Bus 0.1% 0.5% 0.2%
Bike 10.3% 8.1% 4.9%
Total 100% 100% 100% 100% 100% 100%
* Distribution of daily person miles of travel per person by mode of transportation.
2017 NHTS sample was address-based and among other changes included more urban and cell phone only households than
prior years.
Modal Shift in the Boulder Valley: 1990-2023
Page 37
A large decrease in the proportion of work commute trips made by personal vehicle was observed
among Boulder Valley residents; from 76.5% in 1990 to 51.5% in 2023, representing an average
annual decrease of 0.76%. However, in the U.S., from 1990 to 2022, the proportion of work commute
trips made by personal vehicle increased by 5.8.
Figure 59: Modal Split of Work Commute Trips, Boulder Compared to the U.S.
Travel Mode Boulder U.S. NHTS/NPTS*
2023 2009 1990 2022 2009 1990
SOV 46.6% 51.5% 47.4% 55.9% 66.6% 76.5% 93.6% 89.4% 87.8% MOV 4.9% 8.5% 9.9%
Public Transportation/Transit 7.5% 9.7% 4.0% 2.7% 5.1% 5.3%
Walk 10.9% 11.1% 8.9% 2.5% 2.8% 4.0%
Bike/Other 30.0% 23.3% 10.6% 1.1% 2.7% 2.9%
Total 100% 100% 100% 100% 100% 100%
* This is not mode used on travel day it is the distribution of workers by usual commute mode (percent of workers).
2017 NHTS sample was address-based and among other changes included more urban and cell phone only households than
prior years.
Likewise, in examining the number of miles traveled for the work commute by personal vehicle, an
average annual decrease of 0.21% was observed among Boulder Valley residents from 1990 to 2023,
while the proportion of miles traveled for the work commute by personal vehicle remained stable in
the same time frame among the U.S. as a whole.
Figure 60: Modal Split of Work Commute Miles, Boulder Compared to the U.S.
Travel Mode Boulder NHTS/NPTS
2023 2009 1990 2022 2009 1990
SOV 66.9% 75.9% 59.7% 68.8% 71.9% 82.8% 94.1% 94.9% 94.5% MOV 9.0% 9.1% 10.9%
Public Transportation/ Transit 10.1% 19.5% 11.2% 2.2% 4.2% 2.6%
Walk 1.4% 13.8% 1.1% 11.7% 1.3% 6.0% 3.7% 0.9% 2.9% Bike 12.4% 10.6% 4.7%
Total 100% 100% 100% 100% 100% 100%
*Distribution of daily person miles of travel per person by mode of transportation and trip purpose (calculated from miles
traveled to work)
2017 NHTS sample was address-based and among other changes included more urban and cell phone only households than
prior years.
Modal Shift in the Boulder Valley: 1990-2023
Page 38
Appendix B. Modal Split by Characteristics
This section contains breakdowns of modal split of all trips, and modal split of work commute trips
by respondent characteristics. It also displays the percentage of respondents making at least one trip
by each mode on the assigned travel day by respondent characteristics. Figure 61 below displays the
proportions of survey participants in each of the categories displayed on the following pages.
Where differences between subgroups are statistically significant, they are marked with an upper -
case letter. an uppercase letter denoting significance is shown in the cell with the larger column
proportion. The letter denotes the subgroup with the smaller column proportion from which it is
statistically different. Subgroups that have no uppercase letter denotation in their column and that
are also not referred to in any other column were not statistically different.
Figure 61: Respondent Characteristics
Survey Respondent Characteristic Percent of Respondents
Sex of Respondent1 Male 52%
Female 48%
Age of Respondent
16-34 57%
35-54 25%
55+ 19%
CU Student Status CU student 18%
Not a student 82%
Tenure Owner-Occupied 47%
Renter-Occupied 53%
Type of Housing Unit Attached housing unit 60%
Single family, detached 40%
Children in Household No children 77%
Have children 23%
Vehicles to Driver Ratio Less than 1 vehicle per driver 42%
1 or more vehicles per driver 58%
Bikes in household Yes, at least one bike 70%
No bikes 30%
Eco-Pass Status No, don't have 55%
Yes, have Eco-Pass 45%
Type of Day Weekend 25%
Weekday 75%
Race/Ethnicity2
White alone, not Hispanic 84%
Hispanic and/or other race 16%
1. The gender variable excludes “Identify another way’ and ‘Prefer not to say’. 2. Race/Ethnicity combines two
different questions. For full frequencies see Figure 62 on next page.
Modal Shift in the Boulder Valley: 1990-2023
Page 39
Figure 62: Full Frequencies for Gender, Ethnicity and Race Questions
Survey Respondent Characteristic Percent of Respondents
Sex of Respondent
Male 50%
Female 47%
Identify another way 1%
Prefer not to say 2%
Ethnicity Hispanic, Latino, or Spanish origin 8%
Not Hispanic, Latino, or Spanish origin 92%
Race
American Indian or Alaskan Native 0%
Asian 6%
Black or African American 1%
Native Hawaiian or Other Pacific Islander 0%
White 90%
Not listed 3%
Prefer not to say 3%
Modal Shift in the Boulder Valley: 1990-2023
Page 40
Figure 63: Modal Split of All Trips by Respondent Characteristics, part 1
Modal Split of All Trips
Sex of Respondent Age of Respondent CU Student?
Female
(A)
Male
(B)
16-34
(A)
35-54
(B)
55+
(C)
NOT a
student
(A)
CU
student
(B)
Single-Occupancy Vehicle 37.8%
B
31.8% 29.2% 35.7%
A
46.4%
A B
37.6%
B
20.7%
Multiple-Occupancy Vehicle with Adults Only 16.2%
B
13.7% 14.4%
B
10.7% 21.2%
A B
16.5%
B
7.4%
Multiple-Occupancy Vehicle with Children 8.4%
B
5.2% 3.4% 16.1%
A C
4.1% 7.3%
B
3.9%
Bus (Transit), including School Bus 3.6% 4.3% 6.0%
B C
2.3% 1.8% 2.9% 10.0%
A
Bicycle 8.9% 16.6%
A
14.7%
C
15.1%
C
5.8% 11.0% 21.8%
A
E-bike 2.8% 3.5% 3.5%
C
3.7%
C
1.0% 2.9% 3.8%
E-scooter 0.0% 0.2% 0.1%
0.0% 0.0% 0.1% 0.0%
Foot 22.3% 24.7% 28.6%
B C
16.4% 19.7% 21.7% 32.3%
A
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
N=1920 N=2054 N=2273 N=991 N=758 N=3325 N=753
Figure 64: Modal Split of All Trips by Respondent Characteristics, part 2
Modal Split of All Trips
Have Children? Tenure Status Type of Housing Unit
No children
(A)
Have children
(B)
Owner-
Occupied
(A)
Renter-
Occupied
(B)
Attached
(Multi-Family
Housing)
(A)
Detached
(Single-
Family)
(B)
Single-Occupancy
Vehicle
37.6%
B
32.2% 41.6%
B
28.0% 30.5% 40.5%
A
Multiple-Occupancy
Vehicle with Adults Only
15.5%
B
6.0% 14.9% 15.0% 15.0% 14.1%
Multiple-Occupancy
Vehicle with Children
3.0% 30.8%
A
11.0%
B
2.8% 2.8% 12.4%
A
Bus (Transit), including
School Bus
4.5%
B
1.8% 2.2% 6.1%
A
5.2%
B
2.8%
Bicycle 13.1%
B
9.8% 9.4% 16.1%
A
14.5%
B
10.8%
E-bike 1.9% 5.2%
A
3.0% 3.1% 2.4% 4.1%
A
E-scooter 0.0% 0.0% 0.0% 0.1% 0.1% 0.0%
Foot 24.5%
B
14.1% 18.0% 28.8%
A
29.5%
B
15.4%
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
N=2131 N=598 N=1874 N=2056 N=2356 N=1565
Modal Shift in the Boulder Valley: 1990-2023
Page 41
Figure 65: Modal Split of All Trips by Respondent Characteristics, part 3
Modal Split of All Trips
Ratio of Autos to Drivers HH own any bikes? Race/Ethnicity
Less than 1
vehicle per
driver
(A)
1 or more
vehicles
per driver
(B)
Yes
(A)
No
(B)
White
alone, not
Hispanic
(A)
Hispanic
and/or
other race
(B)
Single-Occupancy Vehicle 25.5% 42.5%
A
33.0% 39.8%
A
33.7% 34.0%
Multiple-Occupancy Vehicle with Adults
Only
12.6% 16.6%
A
15.4% 14.1% 15.5%
B
12.2%
Multiple-Occupancy Vehicle with Children 7.1% 6.3% 7.1%
B
5.5% 6.5% 7.8%
Bus (Transit), including School Bus 5.5%
B
2.9% 4.0% 4.3% 3.7% 8.0%
A
Bicycle 17.4%
B
10.2% 15.5% 8.0% 13.1% 10.7%
E-bike 7.7%
B
1.4% 2.7% 8.0%
A
2.9% 4.5%
A
E-scooter 0.1% 0.1% 0.0% 0.4%
A
0.0% 0.5%
A
Foot 24.0%
B
19.8% 22.2% 19.9% 24.5% 22.3%
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
N=1950 N=2641 N=3247 N=1380 N=3316 N=610
Figure 66: Modal Split of All Trips by Respondent Characteristics, part 4
Modal Split of All Trips
Have an Eco-Pass? Day of the Week Telework Status
No, don't
have
(A)
Yes, have
Eco-Pass
(B)
Weekend
(A)
Weekday
(B)
Do not
telework
(A)
Do
telework
(B)
Single-Occupancy Vehicle 41.3%
B
26.0% 25.5% 37.7%
A
38.4%
B
30.8%
Multiple-Occupancy Vehicle with
Adults Only
17.7%
B
11.4% 23.5%
B
12.5% 11.3% 15.0%
A
Multiple-Occupancy Vehicle with
Children
6.9% 6.6% 9.4%
B
5.5% 4.8% 7.4%
A
Bus (Transit), including School
Bus
2.1% 7.0%
A
2.7% 4.7%
A
4.9% 4.5%
Bicycle 7.8% 19.0%
A
14.3% 12.4% 11.1% 15.4%
A
E-bike 2.4% 3.9%
A
2.0% 3.5%
A
7.2%
B
2.2%
E-scooter 0.0%
0.2% 0.0% 0.1% 0.4% 0.0%
Foot 21.7% 26.0%
A
22.5% 23.6% 21.8% 24.7%
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
N=2202 N=1813 N=1071 N=3138 N=783 N=2390
Figure 67: Modal Split of Work Commute Trips by Respondent Characteristics, part 1
Modal Shift in the Boulder Valley: 1990-2023
Page 42
Modal Split of Work Commute Trips
Sex of
Respondent Age of Respondent CU Student?
Female
(A)
Male
(B)
16-34
(A)
35-54
(B)
55+
(C)
NOT a
student
(A)
CU
student
(B)
Single-Occupancy Vehicle 60.0%
B
36.0% 44.4% 48.1% 65.7% 56.5%
B
11.2%
Multiple-Occupancy Vehicle with Adults Only 2.9%
1.7% 1.0% 5.0% 3.1% 1.9% 3.2%
Multiple-Occupancy Vehicle with Children 0.6% 4.2%
A
2.6% 1.1% 3.4% 3.1% 0.0%
Bus (Transit), including School Bus 6.5%
10.4% 8.4% 9.7% 5.4% 8.3% 9.1%
Bicycle 15.1% 35.0%
A
29.3%
C
26.0%
C
2.4% 17.2% 61.2%
A
E-bike 1.4%
1.5% 0.0% 3.8% 6.0% 1.8% 0.0%
Foot 13.5%
11.3% 14.3% 6.4% 14.1% 11.2% 15.3%
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
N=153 N=181 N=227 N=87 N=24 N=272 N=70
Figure 68: Modal Split of Work Commute Trips by Respondent Characteristics, part 2
Modal Split of Work
Commute Trips
Have Children? Tenure Status Type of Housing Unit
No children
(A)
Have children
(B)
Owner-
Occupied
(A)
Renter-
Occupied
(B)
Attached
(Multi-Family
Housing)
(A)
Detached
(Single-
Family)
(B)
Single-Occupancy Vehicle 53.0% 65.5% 50.3% 45.7% 40.8% 59.7%
A
Multiple-Occupancy
Vehicle with Adults Only
2.8% 6.9% 3.8% 1.1% 2.2% 2.1%
Multiple-Occupancy
Vehicle with Children
0.9% 2.9% 6.2% 0.0% 0.0% 7.0%
Bus (Transit), including
School Bus
5.6% 8.9% 6.9% 9.5% 11.0%
B
3.7%
Bicycle 28.2%
B
10.7% 23.3% 27.5% 29.4% 19.9%
E-bike 1.7% 5.1% 2.8% 0.5% 0.5% 3.2%
A
Foot 7.7% 0.0% 6.6% 15.8%
A
16.2%
B
4.3%
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
N=188 N=34 N=138 N=207 N=225 N=121
Modal Shift in the Boulder Valley: 1990-2023
Page 43
Figure 69: Modal Split of Work Commute Trips by Respondent Characteristics, part 3
Modal Split of Work Commute
Trips
Ratio of Autos to Drivers HH own any bikes? Race/Ethnicity
Less than 1
vehicle per
driver
(A)
1 or more
vehicles per
driver
(B)
Yes
(A)
No
(B)
White
alone, not
Hispanic
(A)
Hispanic
and/or
other race
(B)
Single-Occupancy Vehicle 34.0% 54.0%
A
48.5% 41.2% 46.7% 46.3%
Multiple-Occupancy Vehicle with
Adults Only
5.3%
B
0.7% 1.1% 5.9%
A
2.8% 0.5%
Multiple-Occupancy Vehicle with
Children
1.2% 3.2% 2.8% 1.7%
0.7% 8.2%
A
Bus (Transit), including School
Bus
7.0% 8.3% 9.3% 3.9%
6.4% 16.1%
A
Bicycle 37.8%
B
22.3% 29.5% 24.5% 31.7%
B
7.8%
E-bike 2.9%
1.1% 1.6% 2.3% 1.3% 2.1%
Foot 11.6% 10.5% 7.2% 20.6%
A
10.4% 19.0%
A
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
N=144 N=239 N=278 N=105 N=251 N=82
Figure 70: Modal Split of Work Commute Trips by Respondent Characteristics, part 4
Modal Split of Work Commute
Trips
Have an Eco-Pass? Day of the Week Telework Status
No, don't
have
(A)
Yes, have
Eco-Pass
(B)
Weekend
(A)
Weekday
(B)
Do not
telework (A)
Do telework
(B)
Single-Occupancy Vehicle 75.2%
B
26.2% 53.9% 46.3% 59.6%
B
40.8%
Multiple-Occupancy Vehicle with
Adults Only
2.0% 1.5% 3.4% 2.6%
3.8% 1.4%
Multiple-Occupancy Vehicle with
Children
4.5%
B
0.9% 20.7%
B
0.8% 6.7%
B
0.4%
Bus (Transit), including School
Bus
4.4% 11.7%
A
11.1% 8.4% 3.6% 10.5%
A
Bicycle 7.4% 40.6%
A
9.5% 27.2%
A
14.2% 32.5%
A
E-bike 2.0%
1.0% 1.3% 1.4% 1.5% 1.4%
Foot 4.6% 18.1%
A
0.0% 13.1% 10.6% 13.0%
Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
N=152 N=192 N=28 N=318 N=114 N=228
Modal Shift in the Boulder Valley: 1990-2023
Page 44
Figure 71: Modal Split of All Trips by CU Student Characteristics
Modal Split of All Trips
Sex of Respondent Race/Ethnicity
Female
(A)
Male
(B)
White alone, not
Hispanic
(A)
Hispanic and/or
other race
(B)
Single-Occupancy
Vehicle
25.8%
B
17.7% 19.1% 21.1%
Multiple-Occupancy
Vehicle with Adults Only
6.9% 8.3% 7.5% 8.9%
Multiple-Occupancy
Vehicle with Children
8.7%
B
0.9% 4.1% 4.0%
Bus (Transit), including
School Bus
9.9% 9.3% 10.2% 12.0%
Bicycle 15.7% 25.2%
A
23.4%
B
7.3%
E-bike 0.9% 6.1%
A
4.6% 1.0%
Foot 32.0% 32.6% 31.1% 45.9%
A
Total 100.0% 100.0% 100.0% 100.0%
N=290 N=430 N=597 N=125
Figure 72: Modal Split of Work Commute Trips by CU Student Characteristics
Modal Split of Work
Commute Trips
Sex of Respondent Race/Ethnicity
Female
(A)
Male
(B)
White alone, not
Hispanic
(A)
Hispanic and/or other
race
(B)
Single-Occupancy
Vehicle
15.8% 6.5% 4.9% 35.7%
A
Multiple-Occupancy
Vehicle with Adults Only
0.0% 5.9% 4.5% 0.0%
Multiple-Occupancy
Vehicle with Children
0.0% 0.0% 0.0% 0.0%
Bus (Transit), including
School Bus
0.0% 16.4% 12.8% 0.0%
Bicycle 47.6%
65.4% 67.5% 0.0%
Foot 36.6%
B
5.9% 10.3% 64.3%
A
Total 100.0% 100.0% 100.0% 100.0%
N=23 N=39 N=50 N=9
Modal Shift in the Boulder Valley: 1990-2023
Page 45
Figure 73: Percent of Respondents Making at Least One Trip Using Each Mode by Respondent
Characteristics, part 1
Travel Mode
Sex of Respondent Age of Respondent CU Student?
Female
(A)
Male
(B)
16-34
(A)
35-54
(B)
55+
(C)
NOT a
student
(A)
CU
student
(B)
Single-Occupancy Vehicle 54.4% 48.0% 45.7% 60.4%
A C
50.4% 55.0%
B
30.4%
Multiple-Occupancy Vehicle with Adults Only 33.5% 28.3% 30.5% 32.4% 28.5% 32.4%
B
20.6%
Multiple-Occupancy Vehicle with Children 13.5% 9.7% 7.1% 27.6%
A C
5.0% 12.6%
B
5.5%
Bus (Transit), including School Bus 8.1% 11.4% 15.6%
B C
6.0% 2.6% 6.9% 25.0%
A
Bicycle 14.9% 27.9%
A
27.0%
C
24.3%
C
8.4% 18.7% 34.7%
A
E-bike 3.6% 3.8% 3.8% 5.6%
C
1.6% 3.4% 4.6%
E-scooter 0.1%
0.7% 0.7% 0.0% 0.1% 0.5% 0.0%
Foot 41.6% 41.5% 51.5%
B C
34.2% 29.1% 39.4% 50.5%
A
Number N=427 N=451 N=463 N=209 N=218 N=752 N=154
Note: Numbers in each cell represent the proportion of respondents who made at least ONE trip by that mode
Figure 74: Percent of Respondents Making at Least One Trip Using Each Mode by Respondent
Characteristics, part 2
Travel Mode
Have Children? Tenure Status Type of Housing Unit
No children
(A)
Have children
(B)
Population in
Owner-
Occupied
Home
(A)
Population in
Renter-
Occupied
Home
(B)
Attached
(Multi-Family
Housing)
(A)
Detached
(Single-
Family)
(B)
Single-Occupancy
Vehicle
49.5% 72.7%
B
60.7%
B
42.5% 45.5% 59.6%
A
Multiple-Occupancy
Vehicle with Adults Only
28.6% 44.0%
B
30.7% 30.5% 28.8% 32.1%
Multiple-Occupancy
Vehicle with Children
7.0% 66.6%
B
17.5%
B
5.9% 6.0% 19.1%
A
Bus (Transit), including
School Bus
9.9% 8.8% 6.3% 13.7%
A
12.3%
B
7.0%
Bicycle 21.8% 13.8% 15.6% 27.0%
A
23.9% 18.5%
E-bike 5.6% 5.7% 4.2% 3.1% 2.1% 5.8%
A
E-scooter 0.5%
0.0% 0.1% 0.7% 0.6% 0.0%
Foot 38.2% 28.7% 33.8% 48.6%
A
49.5%
B
30.5%
Number N=962 N=74 N=432 N=465 N=528 N=368
Note: Numbers in each cell represent the proportion of respondents who made at least ONE trip by that mode
Modal Shift in the Boulder Valley: 1990-2023
Page 46
Figure 75: Percent of Respondents Making at Least One Trip Using Each Mode by Respondent
Characteristics, part 3
Travel Mode
Ratio of Autos to Drivers HH own any bikes? Race/Ethnicity
Less than 1
vehicle per
driver
(A)
1 or more
vehicles per
driver
(B)
Yes
(A)
No
(B)
White
alone, not
Hispanic
(A)
Hispanic
and/or
other race
(B)
Single-Occupancy Vehicle 35.7% 59.2%
A
52.2% 48.9% 50.7% 47.6%
Multiple-Occupancy Vehicle with
Adults Only
25.0% 32.8%
A
31.6%
B
25.4% 31.3% 26.3%
Multiple-Occupancy Vehicle with
Children
11.6% 11.4% 13.1%
B
7.2% 10.6% 16.6%
A
Bus (Transit), including School
Bus
14.2%
B
7.4% 9.1% 11.5% 8.4% 21.5%
A
Bicycle 27.3%
B
18.0% 26.3%
B
10.0% 22.0% 17.1%
E-bike 5.9%
B
2.0% 3.5% 10.2%
A
3.3% 6.3%
E-scooter 0.0% 0.6% 0.0% 1.6%
A
0.0% 2.3%
A
Foot 49.0%
B
36.8% 40.9%
B
30.0% 42.6% 37.4%
Number N=313 N=589 N=715 N=321 N=731 N=137
Note: Numbers in each cell represent the proportion of respondents who made at least ONE trip by that mode
Figure 76: Percent of Respondents Making at Least One Trip Using Each Mode by Respondent
Characteristics, part 4
Travel Mode
Have an Eco-Pass? Day of the Week Telework Status
No, don't
have
(A)
Yes, have Eco-
Pass
(B)
Weekend
(A)
Weekday
(B)
Do not
telework
(A)
Do
telework
(B)
Single-Occupancy Vehicle 43.4% 56.6%
A
42.9% 54.7%
A
51.4% 51.4%
Multiple-Occupancy Vehicle with
Adults Only
26.4% 33.1%
A
36.5%
B
28.0% 27.4% 32.4%
Multiple-Occupancy Vehicle with
Children
11.0% 12.0% 12.7% 10.3% 13.0% 12.3%
Bus (Transit), including School Bus 17.6%
B
4.2% 6.3% 11.3%
A
11.6% 11.5%
Bicycle 28.9%
B
14.9% 23.0% 20.5% 20.8% 26.5%
E-bike 4.7% 2.8% 2.5% 4.0% 7.9%
B
2.7%
E-scooter 0.8% 0.0% 0.0% 0.5% 1.9%
B
0.0%
Foot 44.9%
B
37.9% 36.4% 42.1% 38.9% 45.6%
Number N=394 N=501 N=269 N=674 N=164 N=499
Note: Numbers in each cell represent the proportion of respondents who made at least ONE trip by that mode
Modal Shift in the Boulder Valley: 1990-2023
Page 47
Appendix C. Transportation Market Segmentation
In order to better understand the types of “markets” in respect to Boulder residents’ transportation
mode choices, the 2023 travel diary dataset was analyzed using an analysis technique referred to as
cluster analysis or market segmentation. This analysis sorted respondents into the “clusters,” that is,
groups in which respondents’ responses were most similar to other respondents within the same
group and different from respondents’ responses in other groups. A brief description of the analysis
procedure can be found in Appendix E. Study Methodology. For this analysis, the variables used were
the percent of trips made on the Travel Diary by each of five modes: drive alone (single-occupancy
vehicle), carpool (multiple-occupancy vehicle), bus (transit and school bus), bicycle and walk. Five
groups emerged, with the preponderance of trips being made by each of the five modes in each of the
five groups. A sixth group was formed of those study participants who had not left the house on their
assigned travel day. These six groups were:
Figure 77: Percent of Respondents in Each Transportation Segment
Mostly drive
alone, 30.5%
Mostly carpool,
24.2%
Mostly
bus, 2.2%
Mostly
bike, 15.6%
Mostly walk,
19.8%Did not leave
house, 7.7%
Modal Shift in the Boulder Valley: 1990-2023
Page 48
KEY CHARACTERISTICS OF THE TRANSPORTATION SEGMENTS
The key characteristics of the six transportation segments are shown in the following table. Detailed
tables showing selected survey results by transportation segment are presented on the pages
following.
Figure 78: Key Characteristics of the Transportation Segments
Segment Percent of
Population
Average Percent
of Trips Made
Via Each Mode
Other Characteristics
Mostly
drive
alone
31%
SOV, 86%
MOV, 7%
Bus, 0%
Bike, 2%
Foot, 5%
• Highest proportion of households with one or more vehicles per driver (83%).
• Highest proportion of those who do not have an Eco-Pass (69%).
• Highest proportion of home owners (60%).
• Highest proportion of those who substituted a trip with a delivery (55%).
• Highest proportion of those who do not telework or do it occasionally (45%).
Mostly
carpool 24%
SOV, 15%
MOV, 71%
Bus, 1%
Bike, 3%
Foot, 10%
• Lowest proportion of those who work on Boulder (40%).
• Highest proportion of residents who telecommute every day (32%).
• Highest proportion of households that received any goods/services by delivery (28%).
• Close to highest in households with one or more vehicles per driver (72%).
• Close to highest of employees who work full-time (62%).
Mostly
walk 20%
SOV, 12%
MOV, 5%
Bus, 7%
Bike, 2%
Foot, 74%
• High proportion of those who use Eco-pass more than once a week (32%).
• High proportion of those aged 18-34 (67%).
• High proportion of those who live in attached places (74%).
• Lowest proportion of employees who telecommuted on the day of the survey (25%).
Mostly
bike 16%
SOV, 8%
MOV, 3%
Bus, 2%
Bike, 76%
Foot, 11%
• Highest of employees who work full-time (64%).
• High proportion of employed people who work in Boulder (73%).
• Low proportion of households that received goods/services by delivery (10%).
• High proportion of residents that have an Eco-Pass (66%).
• Highest proportion of households that owned a bicycle (99%).
• Highest proportion of male members (68%).
Mostly
bus 2%
SOV, 0%
MOV, 2%
Bus, 94%
Bike, 0%
Foot, 5%
• Highest proportion of members with an Eco-Pass (74%).
• Highest proportion of CU students (64%).
• Highest proportion of members aged 18 to 34 (85%).
• Highest proportion of renters (80%).
• Highest proportion of weekdays (85%).
• Highest proportion of household with less than one vehicles per driver (78%).
Did not
leave
house
8% No trips made
• Least likely to be employed (53% were not employed).
• Less likely to have an Eco-pass (39%).
• Least likely to have a bike in their household (66% had one).
• Highest proportion of members aged 55+ (53%).
• Highest proportion of people with annual household below $50,000 (39%).
Modal Shift in the Boulder Valley: 1990-2023
Page 49
Figure 79: Percent of Trips Made on Assigned Travel Day by Transportation Segment
Percent of Trips Made by: Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
SOV 86% 15% 0% 8% 12% 0% 33%
MOV 7% 71% 2% 3% 5% 0% 21%
Bus 0% 1% 94% 2% 7% 0% 4%
Bike 2% 3% 0% 76% 2% 0% 14%
Foot 5% 10% 5% 11% 74% 0% 20%
Figure 80: Employment Status by Transportation Segment
Are you employed? Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
No 29% 24% 14% 14% 26% 53% 26%
Yes, part-time 13% 14% 43% 22% 18% 16% 16%
Yes, full-time 58% 62% 43% 64% 57% 30% 57%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 81: City of Employment by Transportation Segment
City where respondent
works
Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Boulder 57% 48% 73% 73% 59% 76% 60%
Other 43% 52% 27% 27% 41% 24% 40%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 82: Frequency of Telecommuting by Transportation Segment
How often, if ever, do you
telecommute for work?
(Among those who are
employed.)
Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Every work day
(I always work from my home)
20% 32% 2% 20% 21% 25% 23%
2 to 4 times per week 28% 37% 42% 28% 35% 28% 32%
Once or twice a month 7% 9% 19% 21% 13% 3% 11%
Occasionally 11% 5% 0% 13% 10% 7% 9%
Never 34% 17% 38% 18% 21% 37% 24%
Total 100% 100% 100% 100% 100% 100% 100%
Modal Shift in the Boulder Valley: 1990-2023
Page 50
Figure 83: Telecommuting Status on Assigned Travel Day by Transportation Segment
Telecommuted on the day of
the survey?
(Among those who are
employed and at least
occasionally telework.)
Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
No 67% 63% 45% 71% 75% 47% 68%
Yes 33% 37% 55% 29% 25% 53% 32%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 84: Receipt of Goods or Services via Delivery by Transportation Segment
Receive any goods or
services by delivery?
Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
No 80% 72% 96% 90% 79% 77% 80%
Yes 20% 28% 4% 10% 21% 23% 20%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 85: Substitution of Travel by Deliveries by Transportation Segment
Did deliveries substitute for
travel?
Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
No 45% 75% 100% 67% 59% 82% 62%
Yes 55% 25% 0% 33% 41% 18% 38%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 86: Eco-Pass Status by Transportation Segment
Eco-Pass status Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Yes, have an Eco-Pass 31% 37% 74% 66% 53% 39% 44%
No, don’t have an Eco-Pass 69% 63% 26% 34% 47% 61% 56%
Total 100% 100% 100% 100% 100% 100% 100%
Modal Shift in the Boulder Valley: 1990-2023
Page 51
Figure 87: Frequency of Use of Eco-Pass by Transportation Segment
Number of times use
Eco-pass
Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
More than once a week 6% 20% 52% 18% 32% 14% 20%
About once a week 2% 9% 20% 18% 10% 9% 10%
About once every two weeks 11% 9% 0% 15% 6% 12% 10%
About once a month 14% 9% 28% 33% 19% 11% 18%
Less than once a month 42% 29% 0% 10% 20% 30% 25%
Haven’t used 14% 6% 0% 4% 7% 15% 8%
Haven’t picked-up or activated 11% 18% 0% 1% 6% 9% 9%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 88: Ratio of Autos to Drivers by Transportation Segment
Ratio of Autos to Drivers Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Less than 1 vehicle per driver 17% 28% 78% 52% 46% 42% 35%
1 or more vehicles per driver 83% 72% 22% 48% 54% 58% 65%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 89: Household Bicycle Ownership by Transportation Segment
Household own any
bicycles?
Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Yes 61% 74% 60% 86% 70% 56% 69%
No 39% 26% 40% 14% 30% 44% 31%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 90: Sex of Respondent by Transportation Segment
Sex of Respondent Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Male 47% 47% 43% 68% 53% 49% 52%
Female 53% 53% 57% 32% 47% 50% 48%
Total 100% 100% 100% 100% 100% 100% 100%
Modal Shift in the Boulder Valley: 1990-2023
Page 52
Figure 91: Age of Respondent by Transportation Segment
Age of Respondent Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
18-34 44% 44% 85% 66% 67% 32% 52%
35-54 26% 32% 10% 25% 15% 14% 23%
55+ 31% 24% 5% 9% 19% 53% 24%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 92: CU Student Status by Transportation Segment
Student Status Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
NOT a student 91% 93% 36% 67% 77% 84% 83%
Student 9% 7% 64% 33% 23% 16% 17%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 93: Housing Tenure by Transportation Segment
Tenure Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Rent 40% 44% 80% 69% 60% 54% 52%
Own 60% 56% 20% 31% 40% 46% 48%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 94: Type of Housing Unit by Transportation Segment
Type of Housing Unit Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Attached (Multi-Family) 51% 48% 80% 64% 74% 65% 59%
Detached (Single-Family) 49% 52% 20% 36% 26% 35% 41%
Total 100% 100% 100% 100% 100% 100% 100%
Modal Shift in the Boulder Valley: 1990-2023
Page 53
Figure 95: Annual Household Income by Transportation Segment
Annual Household Income Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Less than $10,000 2% 3% 19% 3% 4% 7% 4%
$10,000 to $19,999 2% 0% 9% 3% 2% 9% 2%
$20,000 to $29,999 3% 1% 0% 3% 1% 10% 2%
$30,000 to $39,999 2% 3% 0% 13% 6% 3% 5%
$40,000 to $49,999 6% 0% 1% 5% 3% 10% 4%
$50,000 to $74,999 10% 4% 13% 8% 12% 8% 8%
$75,000 to $99,999 10% 9% 0% 3% 9% 11% 8%
$100,00 to $149,999 18% 23% 15% 19% 21% 17% 20%
$150,000 or more 33% 43% 26% 34% 29% 12% 33%
Prefer not to say 14% 13% 18% 11% 13% 13% 13%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 96: Day of Assigned Travel by Transportation Segment
Day of the Week Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Weekend 22% 42% 15% 24% 23% 40% 29%
Weekday 78% 58% 85% 76% 77% 60% 71%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 97: Gender by Transportation Segment
Gender Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
Female 53% 53% 57% 32% 47% 50% 49%
Male 47% 47% 43% 68% 53% 50% 51%
Total 100% 100% 100% 100% 100% 100% 100%
Figure 98: Race/Ethnicity by Transportation Segment
Race/Ethnicity Mostly
drive alone
Mostly
carpool
Mostly
bus
Mostly
bike
Mostly
walk
Did not
leave
house
Overall
White alone, not Hispanic 83% 86% 77% 84% 85% 84% 84%
Hispanic and/or other race 17% 14% 23% 16% 15% 16% 16%
Total 100% 100% 100% 100% 100% 100% 100%
Modal Shift in the Boulder Valley: 1990-2023
Page 54
Appendix D. References
• Howard Needles Tammen and Bergendoff: “Transportation Master Plan for the
Boulder Valley”; October 1989.
• Charlier Associates, Inc.: “Transportation Master Plan Update for the Boulder Valley”;
July 1996.
• City of Boulder, LSA Associates, Inc: “Transportation Master Plan 2003”, September
2003.
• City of Boulder, LSA Associates, Inc: “Transportation Master Plan 2008”, September
2008.
• Miller MA, Miller TI: “The 1990 Diary Study of Boulder Valley”; January 1991.
• Miller MA, Miller TI. “Modal Shift in the Boulder: 1990 to 1992”; January 1993.
• Miller MA: “Modal Shift in the Boulder Valley: 1990 to 1994”; February 1995.
• Caldwell EM: “Modal Shift in the Boulder Valley: 1990 to 1996”; March 1997.
• Caldwell EM: “Modal Shift in the Boulder Valley: 1990 to 1998”; February 1999.
• Parker D, Baron D: “Modal Shift in the Boulder Valley: 1990 to 2000”; February 2001.
• Caldwell EM: “Modal Shift in the Boulder Valley: 1990 to 2003”; 2004.
• Caldwell EM, Paula M: “Modal Shift in the Boulder Valley: 1990 to 2006”; July 2007.
• Puget Sound Council of Governments: “Household Travel Surveys, 1985-1988 Puget
Sound Region”; June 1990.
• U.S. Department of Transportation, Federal Highway Administration: “Summary of
Travel Trends, 2009 National Household Travel Survey, FHWA-PL-11-022,
Washington, DC; 2011.
• U.S. Department of Transportation, Federal Highway Administration: “Summary of
Travel Trends, 2017 National Household Travel Survey, FHWA-PL-18-019,
Washington, DC; 2018.
• Federal Highway Administration. (2022). 2022 NextGen National Household Travel
Survey Core Data, U.S. Department of Transportation, Washington, DC. Available
online: http://nhts.ornl.gov.
Modal Shift in the Boulder Valley: 1990-2023
Page 55
Appendix E. Study Methodology
The 2023 travel diary study used similar materials to that used in the previous implementations of
the study (1990, 1992, 1994, 1996, 1998, 2000, 2003, 2006, 2009, 2012, 2015 and 2018). In 2015
and 2018 a travel diary app that could be downloaded by survey recipients and used to record trips
made during the day was employed. However, in 2023 the use of the app was discontinued.
STUDY DESIGN
The Travel Diary Study is designed to capture all trips made during a 24-hour period by a random
selection of adults within households in the Boulder Valley. Each selected household is assigned a
specific day on which to complete the travel diary. The study is always scheduled to take place during
the end of September or the beginning of October, as that time period has historically had mild
weather allowing people to use all modes of transportation.
The traditional data collection methodology for the Travel Diary Study is to send a study packet with
the materials needed to complete in the study accompanied by instructions on how to participate to
10,000 randomly selected households within the Boulder Valley. For households in which more than
one adult resides, an adult is randomly selected for the study by requesting that the adult who most
recently had a birthday (regardless of year of birth) complete the study.
In 2015, the City of Boulder invested in developing a new app to simplify tracking for participants
and improve accuracy of route data. The app was used in 2015 and 2018. In 2023 the use of the app
was discontinued for the low responses rate the methodology yielded in 2015 and 2018.
In 2023, 10,000 households were assigned travel days in the first week of October. A packet with a
cover letter explaining the purpose of the study, the diary and household survey and instructions for
the study were mailed to the household several days before their assigned travel day. A postcard
notification was mailed a week before the packet.
Copies of the various travel diary study materials can be found in Appendix F. Data Collection
Materials.
Selecting Survey Recipients
A total of 10,000 households within Boulder Valley were invited to participate in the travel study, as
described above. This number was selected based on the number of people desired to eventually
participate, factoring for the probable non-response and drop-out rates of households. The goal was
to obtain about 1,000 completed travel diaries.
All households located in the Boulder Valley boundaries, defined as zip codes 80301, 80302, 80303,
80304 and 80305 were eligible for the survey. Because local governments generally do not have
inclusive lists of all the residences in the jurisdiction (tax assessor and utility billing databases often
omit rental units), lists from the United States Postal Service (USPS) Delivery Sequence File (DSF),
updated every three months, usually provide the best representation of all households in a specific
geographic location. NRC used the DSF data to select the sample of households. Selected addresses
were processed for certification and verification using CASS™/NCOA software that relies on the USPS
National Directory information to verify and standardize the address elements and assign each a
complete, nine-digit zip code where possible.
Modal Shift in the Boulder Valley: 1990-2023
Page 56
Response Rates
Figure 99 displays the response rates for the 2023 study. If the undeliverable addresses are
eliminated from the sample, about 9,499 households were contacted to participate in the study. Of
these, 998 returned a usable travel diary and/or household survey, representing 11% of everyone
contacted.
Figure 99: Response Rate for the 2023 Travel Diary Study
Number of Recipients
Returned with
Undeliverable
Address
Eligible to Participate Returned a Usable
Travel Diary Response Rate
10,000 501 9,499 998 10.5%
Figure 100: Comparison of Response Rates Across Study Years
Response Rates 2023 2018 2015* 2012 2009 2006 2003 2000 1998 1996 1994 1992 1990*
Percent of entire sample
who completed a travel
diary
11% 9% 11% 15% 15% 18% 18% 19% 19% 18% 20% 20% 25%
*Note: 1990 response rates are for households only, and do not include the response rates of students in group quarters
(dormitories and Greek houses). Response rates among these groups are much lower than among those in households, and
thus 1990 response rates are probably inflated compared to the other years. In 2015, the response rate for the entire sample
was 11%, but for the recipients who were surveyed in the same was as recipients were from 2003 to 2012, the response rate
was 16%.
**Not applicable starting in 2003.
ANALYSIS OF RESULTS
Cleaning and Coding of Data
Once received, the diaries were prepared for analysis. Every diary was examined to ensure that it
was filled out correctly with accurate trip descriptions. A very common mistake in all study years
was to count round trips as one trip rather than two. For ease in keypunch the diary data were
transferred to coding sheets, disregarding origin and destination data which would not be used for
this report. Three other variables were coded at this time: 1) the type of trip made (HW, HO or NH),
2) if the trip was a “link” in the work commute, and 3) if the trip had both origin and destination
outside the Valley boundaries (see Appendix F. Data Collection Materials).
In 1996, a few changes were made to the survey instruments. It was felt that respondents were not
using the “truck” category correctly in previous study years, and quite often trips recorded as having
been made in a truck were changed to automobile, because staff believed respondents were using
the truck category to record trips made in their sports utility vehicle or pick-up truck.
In 2023, a new wave of edits was included in the survey instruments. Car o light track was re-worded
as private vehicle, bus as bus/rail/transit; taxi as Lyft, Uber, Taxi and bicycle was divided into three
categories: bicycle, E-bike and E-scooter. A new travel mode named Via/paratransit was included for
the first time. This changes can be seen in the table on the following page.
Modal Shift in the Boulder Valley: 1990-2023
Page 57
Figure 101: Changes in the Travel Diary methods across Study Years
1990-1994 1996-2018 2023
1. car (driver) 1. car or light truck (driver) 1. private vehicle (driver)
2. car (passenger) 2. car or light truck (passenger) 2. private vehicle (passenger)
3. bus (transit) 3. bus (transit) 3. bus/rail/transit
4. school bus 4. school bus 4. school bus
5. car share
6. taxi (passenger) 7. taxi (passenger) 6. Lyft, Uber, Taxi
5. motorcycle 6. motorcycle 7. motorcycle
7. truck (driver) 5. large truck
8. truck (passenger)
9. bicycle 8. bicycle 8. bicycle
9. E-bike
10. E-scooter
10. walk only 9. walk only 11. walk
12. Via/paratransit
11. other ____________ 10. other _______________ 13. other _______________
Estimating Trip Length
An important element in travel studies such as this one is the length of the trips. Early in the study’s
history, elaborate and expensive geocoding schemes were most often used by coding origins and
destinations by Census tract or transportation zone and inputting these codes into a complex
database which calculates mileage. In the 1990 Diary Study, after researching previous studies and
discerning the difficulties and large expense associated with database systems, the research staff
devised a geocoding scheme which was more attractive in price as well as accuracy. On the diary
document the participants were asked to estimate how many miles each trip had taken them. At
baseline (1990), uncertain of how accurate people are at estimating miles traveled, the research staff
geocoded a random subset of 400 trips, 300 in motorized vehicles and 50 on bike and foot each. The
geocoding was performed with rulers and Boulder Valley maps, where the staff member literally
measured the journey by hand. A rule of thumb derived from transportation planning was used to
save the effort of deciphering which path the participant made to a various destination: multiplying
the distance calculated between locations as the crow flies by 1.5. This formula was believed to work
fairly accurately 90% of the time.7
The geocoded miles were then correlated with the miles estimated by the participants. The estimates
were found to be extremely accurate;8 on average the people overestimated the trips by only .12
miles or 17% of the trip distance. To correct for this overestimation, data extracted from the
regression equation was used to reduce the estimates.9 The adjusted estimates were used for all
analyses using trip length. The same statistical adjustments were made in subsequent years.
Prior to 2000, when trip distance was missing, it was estimated, when possible, by study staff using
the same hand geocoding methodology described above. Beginning in 2000, however, the internet-
7 Chuck Green, DRCOG
8 Simple Correlation of 0.9, p < .001.
9 Equation used to adjust motorized vehicles: adjusted miles = (.88 x estimated miles) + .20
Equation used to adjust non-motorized vehicles: adjusted miles = (.86 x estimated miles) + .10
Modal Shift in the Boulder Valley: 1990-2023
Page 58
based program “MapQuest” (www.mapquest.com/directions) was used to estimate trip distances,
replaced by Google Maps in 2009.
Data Entry, Weighting and Analysis
The data from the travel diary coding sheets and household travel surveys were data entered into
electronic datasets using a key and verify methodology. This means that the data were entered twice,
and the two datasets compared. Where there were discrepancies, the results were compared to the
hard copy survey and keyed correctly. These plain-text datasets were then imported into SPSS®, a
statistical software package, for analysis.
Using the assigned unique identifier, the household travel survey responses were matched with the
travel diary information. Two types of datasets were created: a trip-level dataset, where every record
in the dataset represented a single trip, and a person-level dataset, where every record in the dataset
represented a single person.
Due to the differences in travel behavior by various sociodemographic groups, the participants’
responses were statistically weighted. Using the data from the Census, the results were adjusted to
give more weight to the travel of those who were under represented in the sample. Figure 102 below
displays the sociodemographic profile of the 2023 study participants using unweighted and weighted
data compared to the Census data for comparison.
Figure 102: Comparison of 2023 Weighted and Unweighted Data to Census Population
Estimates
Characteristic Population Profile* Unweighted Data Weighted Data
Day of Week
Sunday 14% 13% 14%
Monday 14% 16% 14%
Tuesday 14% 17% 14%
Wednesday 14% 15% 14%
Thursday 14% 13% 14%
Friday 14% 13% 14%
Saturday 14% 13% 14%
Gender by Age
Female 16-34 24% 8% 24%
Female 35-54 12% 13% 11%
Female 55+ 12% 35% 13%
Male 16-34 29% 10% 28%
Male 35-54 12% 11% 12%
Male 55+ 11% 23% 11%
Housing Type
Attached 60% 45% 59%
Detached 40% 55% 41%
Housing Tenure
Owner 48% 70% 48%
Renter 52% 30% 52%
* ACS 2020 5-year estimates, total population
Modal Shift in the Boulder Valley: 1990-2023
Page 59
For the most part, simple descriptive statistics (e.g., averages and frequencies) are reported in the
body of the report. Crosstabulations and crossbreak analyses (e.g., chi-square and anova) are shown
in Appendix B. Modal Split by Characteristics. In that appendix, differences between subgroups were
considered “statistically significant” if the p-value from the statistical test was less than 0.05; that is,
that there was a less than 5% probability that differences observed were due to chance alone.
A market segmentation analysis was performed on the data. The results of this analysis are shown in
Appendix C. Transportation Market Segmentation. The statistical technique most commonly used to
derive segments from survey data is cluster analysis. The analysis itself sorts cases (respondents)
into the “clusters,” that is, groups in which cases are most similar to other cases within the same
group and different from cases in other groups.
The SPSS procedure “K-Means Cluster Analysis” was used to perform this analysis. The algorithm
employed by this procedure allows larger datasets to be analyzed into “clusters.” Clusters are formed
by comparing responses to a set of selected variables. The procedure seeks patterns of response that
are shared by a number of individuals and that are distinct from other groups of individuals. These
groups are the clusters. This procedure uses continuous (numeric) variables. For this analysis, the
variables used were the percent of trips made by the respondent on the assigned travel day by each
mode: percent of trips made by driving alone, percent of trips made by carpooling, percent of trips
made by transit, percent of trips made by bicycling, and percent of trips made by walking.
Modal Shift in the Boulder Valley: 1990-2023
Page 60
Appendix F. Data Collection Materials
This appendix contains the instruments and materials used for the data collection of the 2023 Travel
Diary Study. Included are:
• Pre-notification postcard
• Diary packet cover letter to Boulder Valley residents
• Travel Diary instructions
• Travel Diary card
• Travel Diary Overflow sheet
• Household Survey
Dear Boulder Valley Resident:
Travel is something we all do and it can be challenging at times. I am inviting a member of your household to
log your travel on a simple diary for a single day the week of October 2, 2023. These travel diaries show how
Boulder residents travel and help us plan to better meet your transportation needs.
This travel diary survey is conducted every few years by a professional research firm and is the major tool to
help the city better understand existing travel patterns. The results will be used in the current Transportation
Master Plan update and to improve our community.
Your household was chosen at random and your participation will be completely confidential. We are only mailing
the diaries to a small number of Boulder Valley residents, so your participation is extremely important and greatly
appreciated.
Your diary packet will arrive in about a week at which time you’ll receive your assigned tracking day.
Many thanks in advance for your help.
Sincerely,
Aaron Brockett, Mayor
City of Boulder
c/o National Research Center, Inc.
2955 Valmont Rd., Suite 300
Boulder, CO 80301-1360
Presorted
First Class Mail
US Postage
PAID
Boulder, CO
Permit NO. 94
bouldercolorado.gov 1001 Arapahoe Ave. Boulder, CO. 80302 303-441-3388
September 2023
Dear Boulder Valley Resident:
Transportation is a key part of everyone’s life. Whether for getting to school or work, shopping, the
grocery store or a local park, access to convenient, safe and affordable transportation is a critical part of
any community. It is the City of Boulder’s responsibility to plan, build, maintain and operate this people-
first transportation system — one where everyone can get where they need to go, no matter how they
choose to travel. To accomplish this, we need your help understanding how people travel in our
community.
Every few years, we turn to you to understand how our community currently travels and how long it
takes, so we can further improve your travel experience. This survey is the primary data source for
understanding the travel patterns of Boulder Valley residents. This research is being conducted by a
professional research firm, Polco/National Research Center. The firm has randomly chosen your
household to participate. Your participation will be completely confidential.
Because we want to understand travel for all of the Boulder Valley community, we need a
representative sample of Boulder residents. That’s why it’s so important that the person in your
household who participates in this travel survey be:
•In town on that day.
•Age 16 or older and who most recently had a birthday.
If this person is willing to help with this simple but very important project, their response will be much
appreciated.
Please complete the survey and write your travel habits using the materials in this packet. Completed
surveys and travel diaries should be mailed to Polco/National Research Center using the enclosed
postage-paid envelope. If you have questions or would like support, please contact Nicolas Solari at
608-690-3233 or at nicolas@polco.us and he’ll be happy to help you.
Thank you very much! Your participation will be helpful to our community and future transportation
planning efforts.
Sincerely,
Aaron Brockett, Mayor
City of Boulder
2023 Travel Diary Study
INSTRUCTIONS
Please review the materials briefly before continuing to read the instructions. If any materials are missing, please
contact Nicolas of Polco, at 608-690-3233 or at nicolas@polco.us, and materials will be mailed to you. This packet
contains:
Cover letter & these instructions Travel Diary Postage paid return envelope
Household Travel Survey Travel Diary overflow sheet
COMPLETE THE TRAVEL DIARY ON YOUR ASSIGNED DAY
▪ Complete the travel diary on Xweekday, OCTOBER Xday, 2023, regardless of the weather or the number and type
of activities planned for that day.
▪ Take the Travel Diary with you on your assigned day. It is the 8½” x 11” card included in this packet.
▪ If you will be out of town or forgot to complete the diary on assigned day, you may complete the diary on the same
day of the next week (Xweekday, October Xreplace).
▪ Report every trip segment you make that is longer than a city block:
- Whether you are a passenger, driver or pedestrian.
- Whether it is recreational (e.g. going for a run) or has a specific destination.
▪ Start the diary after 12:01 am (right after midnight) and continue until 12:00 midnight on your assigned day.
▪ Do not change your travel behavior because you are keeping this diary.
▪ In addition to completing the Diary, please complete the attached short household survey.
▪ Completed surveys and travel diaries should be mailed to Polco using the enclosed postage-paid envelope.
WHAT IS A “TRIP SEGMENT”?
▪ A trip segment is all or part of a one-way journey.
▪ Round-trips count as two trip segments. If you drive to the grocery store and back, record two trip segments on
your diary. The purpose of the first is “shopping,” the second is “return home.”
▪ In addition to round trips, you may need to record one journey as more than one trip segment if:
- You make multiple stops. For example, if you walk your child to school, then catch the bus outside the school to
the grocery store, and then return home, stopping to pick up a prescription at the drugstore, this would count as
four trip segments with the following destinations: the school, the grocery store, the drugstore and then home.
- You change travel method (not including bus transfers). For instance, if you walk more than one block to a bus
stop to take the bus to work, count the bus stop as the first destination and the purpose of that trip segment as
“change travel mode”. The next trip segment destination is work and the purpose is “work commute.”
- You pick up or drop off a passenger. This should be treated as at least two trip segment s. The purpose of the
first trip segment is “drive passenger.”
- If you are on a recreational or exercise loop (walk, run or bike ride) then your “destination” is the half-way point
and you record two trip segments. The purpose of the first is “social/recreation,” the second is “return home.”
QUICK TIPS
➢ For your destination, you may use an address, nearest intersection or commonly recognized buildings, stores or
other specific and unique locations (e.g. “McGuckin Hardware”, or “Table Mesa Park and Ride”)
➢ Keep good estimates of the start and end times. Use the times you started and ended travel and don’t include the
time you spend at the destination. For example, if you go to the store, don’t count the time you are in the store.
When you arrived is the end of the first trip and when you left the store is the start of the second trip.
➢ If using a car for your trip, don’t forget to mark if you were a passenger or driver and fill in the number of adults
(include yourself, those 16 or older with drivers licenses and those over age 18) and the number of children in the
vehicle.
➢ To record mileage, use a vehicle odometer if possible at the beginning and end of each trip. If you wish, you can
record the number of blocks instead of miles if it is easier, but PLEASE write in "blocks" on your form, so we don't
mistake it for miles.
(continued on reverse side)
HOW DO I DESCRIBE THE TRIP TYPE?
Go Home Travel from some location other than your workplace to your usual place of residence.
Work Commute Travel to or from your workplace.
Other Work/
Business
Travel done for work, to someplace other than the workplace.
(E.g., sales calls, trips to purchase office supplies for work.)
Personal Business Travel which is made to obtain services, not products.
(E.g. bank, post office, doctor, auto repair.)
Shopping Travel to shop or to purchase products.
School Travel by a student to college or school.
Travel to school by a teacher or other school employee is a work commute trip.
If you are driving a student to school, the trip should be classified as "drive a passenger.”
Social/ Recreation Travel when no business is transacted.
(E.g., parties, participatory sports, cultural or athletic events, church activities, visits to
friends.)
Eat a Meal Examples include going to a restaurant, going to a friend's house for dinner, or home from
work for lunch. Stops for snacks or refreshments should be classified as "social/recreation".
Drive a Passenger Use this category for trips or stops to pick up or deliver someone to a specific location.
(E.g., taking a friend to the store, picking up a child from school.)
Change Travel
Mode
If you drive your car, walk more than one block, or ride your bike to catch the bus, this is a
"change travel mode" trip. However, if you transfer from one bus to another, it should not be
included in this category because you traveled in buses without changing travel modes. (Be
sure to record all the routes you used to make the trip.)
Other Travel that does not seem to fit in the categories listed should be put in the "other" category.
Please list what the trip purpose was in the blank provided. Also, if you have a question as to
where to put a certain trip because you can't decide between two categories, list it in the
"other" category.
SPECIAL CIRCUMSTANCES
What if you don't go anywhere during the day assigned to you? On the travel diary, fill out your name, address and
the assigned diary date, check the box to indicate that you made no trips. Please continue on the Household Survey. It
is important that we get an accurate picture of travel patterns within Boulder, including the number of people who
make no trips.
What if you have more than 9 trip segments during the day assigned to you? The Travel Diary has space to record up
to 9 trip segments. If you have more than 9 trip segments on your assigned day, please use the overflow sheet. If you
have more than the 21 trip segments than can be recorded on the Diary and overflow sheet, call Nicolas and he will
record your trips over the phone or send you more overflow sheets, or make a copy of the overflow sheet and use that.
What if you work a job that requires frequent travel on the day assigned to you? If you work a job that requires you
to make many trips during the 24-hour period (e.g., cab driver, pizza delivery driver, sales person), please call National
Research Center to receive special instructions for completing your Travel Diary.
The EXAMPLE OF A COMPLETED TRAVEL DIARY on the following page, gives a detailed example that may help you in
completing your form.
If you have ANY questions, please contact Nicolas at Polco at nicolas@polco.us
Thank you very much for your participation in this study.
EXAMPLE OF A COMPLETED PAPER TRAVEL DIARY
In the first half of her day, Jane Smith drove from her home at 3523 N. 16th Street to work at CU, first dropping her 9
year old daughter at University Hill Elementary School.
At noon, Jane walked to the Hill for lunch (5 blocks from the building on campus where she works).
The Travel Diary example shows how Jane’s form would be completed. Please note the following:
1. Jane’s travel to work with her daughter is counted as two trips; the first is with her daughter to the elementary
school -- this trip is designated as “drive a passenger”; the second is from the school to work.
2. Although Jane is going to a “school” (CU), it is for the purpose of work, and is designated as a “work commute”
trip.
3. Jane records her trip (walking) to lunch as well as her trip from lunch back to work (two trips). Her trip back to
the school is recorded as “work commute”, because she is returning to her workplace, although she did not
come straight from home.
EXAMPLE OF A COMPLETED TRAVEL DIARY, Page 1
(example continued on reverse side)
Please remember to
fill in the date of the
day you complete the
travel diary!
Record the location at
which you are
beginning your travel
for the day. If it is your
home (the same
address as in the
information box), you
may just write
"SAME" however be
sure to include the
Nearest Cross
Streets.
Don’t include the
amount of time you
were at the
destination.
Don’t forget to include
yourself as an adult in
the vehicle.
You can also select that you
were a passenger in a car, if
appropriate.
In the second part of Jane’s day, she finished work and picked up her daughter and drove home.
She jogged for two miles in her neighborhood before dinner.
When dinner was over, Jane and her family rode their bikes to the Willow Springs Shopping Center for ice cream.
On the example form, note the following:
1. After work, Jane’s trip to pick up her daughter (even though the daughter is not in the car) is designated as a trip
to “drive a passenger”.
2. Jane counts her jog in the neighborhood as two trips, even though she made no stops between leaving home and
returning home. “Jogging” and “running” are considered “walking” for the purposes of this travel diary.
3. When the family rides their bikes to the shopping center for an ice cream, this is a “snack” and is designated as
“social/recreation” rather than eating a meal.
EXAMPLE OF A COMPLETED TRAVEL DIARY, Page 2
If you have ANY questions, please contact Nicolas at nicolas@polco.us
Thank you very much for your participation in this study.
10
2023 Travel Diary
Please record all of your trip segments, whether you are a passenger, driver, cyclist, scooter-rider, or pedestrian.
The information on the first row is included only as an example. Please refer to the instructions if you are not sure how to record your trips.
Name:
Address
:
City/State/Zip
:
DIARY DATE:
STARTING POINT ADDRESS
Street Address:
City/State/Zip:
Nearest Cross Streets: &
I did not leave the house today: ❑
If using motor vehicle, list odometer reading:
at beginning of day:
at end of day:
Trip
segment
#
DESTINATION
(address, building or
nearest cross streets)
trip segment
start time
trip segment
end time trip segment
purpose travel method
est. trip
segment
miles
number of people in
vehicle (inc. yourself)
hour:min am/pm hour:min am/pm children adults example Foothill Elementary
Broadway &
Grape
7:13 AM 7:22 AM
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other: →
3 miles 1 1
1
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
2
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
3
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
Trip
segment
#
DESTINATION
(address, building or
nearest cross streets)
trip segment
start time
trip segment
end time trip segment
purpose travel method
est. trip
segment
miles
number of people in
vehicle (inc. yourself)
hour:min am/pm hour:min am/pm children adults
4
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
5
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
6
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
7
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
8
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
9
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
3
2023 Overflow Sheet
Trip
segment
#
DESTINATION
(address, building or
nearest cross streets)
trip segment
start time
trip segment
end time trip segment
purpose travel method
est. trip
segment
miles
number of people in
vehicle (incl. yourself)
hour:min am/pm hour:min am/pm children adults
10
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
11
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
12
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
13
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
14
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
15
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
Trip
segment
#
DESTINATION
(address, building or
nearest cross streets)
trip segment
start time
trip segment
end time trip segment
purpose travel method
est. trip
segment
miles
number of people in
vehicle (incl. yourself)
hour:min am/pm hour:min am/pm children adults
16
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
17
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
18
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
19
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
20
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
21
_____________________
___________________ &
_____________________
___ : ___ ___ : ___
1. go home 2. personal business
3. shopping 4. school
5. work commute 6. other work/business
7. social/recreation 8. eat a meal
9. drive passenger 10.change travel mode
11. other →
1. private vehicle (driver) 7. motorcycle
2. private vehicle (passenger) 8. bicycle
3. bus/rail/transit 9. E-bike
4. school bus 10. E-scooter
5. car share 11. walk
6. Lyft, Uber, Taxi 12. Via/paratransit
13. other →
Page 1 of 2
c/o National Research Center, Inc.
2955 Valmont Rd., Suite 300
Boulder, CO 80301-1360
303-444-7863
2023 Travel Diary Study
HOUSEHOLD TRAVEL SURVEY
Please complete the following survey regarding your household and return it with your Travel Diary in the enclosed
postage-paid envelope. The survey should take only a few minutes. It is important because it will help research staff gauge
how representative the people who participate in the diary study are in relation to Boulder Valley residents as a whole. It
also provides additional information on the travel patterns of Boulder Valley residents. Your answers to this survey will be
anonymous and will be reported in group form only. Thank you for your time and help.
GENERAL TRAVEL INFORMATION
1. On the day you completed the travel diary, did you have
any goods or services delivered to your work or home?
❑ no → Go to question #3
❑ yes → From how many different sources
did you receive services/deliveries?
sources
2. Did the delivery or deliveries substitute for a travel trip
you might have made to seek the good or service?
❑ no
❑ yes
3. Are you eligible to have an annual transit pass (Eco-Pass
or University Transit Pass) that allows you unlimited bus
rides?
(Please check all that apply.)
❑ yes, Eco-Pass through my employer
❑ yes, Eco-Pass through my neighborhood
❑ yes, a university student transit pass
❑ yes, a university faculty/staff transit pass
❑ yes, other pass: ___________________
❑ no, I am not eligible for an Eco-Pass or
College Pass → go to #5
4. About how often, on average, do you use your transit
pass?
❑ more than once a week
❑ about once a week
❑ about once every two weeks
❑ about once a month
❑ less often than once a month
❑ haven’t used
❑ haven’t picked-up or activated
5. Are you employed?
❑ no → Go to question #10
❑ yes, part-time
❑ yes, full-time
6. Please indicate the city in or nearest to your primary work
place.
❑ Boulder ❑ Louisville
❑ Denver ❑ Longmont
❑ Broomfield ❑ Lafayette
❑ I work from my home
❑ Other city, specify:
7. Please write in the address, building and/or nearest cross
streets of your primary work place.
Building or address:
Nearest cross
streets:
&
8. On average, how often do you telework (work at home
instead of going into the office)? (Include only full days at
home when you did not travel to your workplace.)
❑ Never
❑ Less than once a month
❑ 1 to 3 days per month
❑ Once a week
❑ 2 times a week
❑ 3 times a week
❑ 4 times a week
❑ 5 times a week or more
9. Did you telecommute on the day you completed the
travel diary?
❑ no
❑ yes
HOUSEHOLD INFORMATION
10. How many passenger vehicles does your household own or
normally have use of?
Cars, SUVs, vans Motorcycles /
and light trucks motor scooters
11. How many usable bicycles, e-bikes or e-scooters does your
household have?
Regular E-Bikes E-scooter
bicycles
12. Please check the one choice below which best describes
the kind of residence in which you live.
❑ a detached single-family home
❑ a duplex or triplex
❑ an apartment
❑ a condominium or townhouse
❑ a mobile home
❑ group quarters (e.g., dormitory, nursing home)
→ go to question #14
❑ other: __________________________
13. Do you rent or own your residence?
❑ rent ❑ own
Page 2 of 2
14. About how much was the TOTAL 2022 income before taxes
for your household as a whole? In the total, please include
income before taxes as well as money from all sources for
all persons living in your household. (For example, include
everyone's income from self-employment, gifts, interest on
savings, social security, AFDC, the value of food stamps
received, pension or disability benefits, child support, as
well as wages, tips and salary.)
❑ Less than $10,000
❑ $10,000 to $19,999
❑ $20,000 to $29,999
❑ $30,000 to $39,999
❑ $40,000 to $49,999
❑ $50,000 to $74,999
❑ $75,000 to $99,999
❑ $100,000 to $149,999
❑ $150,000 or more
❑ Prefer not to say
15. Please record the number of household members in each
of the following age categories. (Please remember to
include yourself.)
Number in
Age category household
0 to 6 years _______
7 to 14 years _______
15 to 17 years _______
18 to 24 years _______
25 to 34 years _______
35 to 44 years _______
45 to 54 years _______
55 to 64 years _______
65 or older _______
16. Are any of the household members students at the
University of Colorado, Boulder campus?
❑ no ❑ yes → How many are:
full-time part time
students students
INDIVIDUAL INFORMATION
17. How frequently do you use the following mobility
devices?
Bike E-bike E-scooter
Never ❑ ❑ ❑
Less than once a month ❑ ❑ ❑
1 to 3 days per month ❑ ❑ ❑
Once a week ❑ ❑ ❑
2 times a week ❑ ❑ ❑
3 times a week ❑ ❑ ❑
4 times a week ❑ ❑ ❑
5 times a week or more ❑ ❑ ❑
18. Which of the following do you use?
Private App /
membership Neither
Bike ❑ ❑ ❑
E-bike ❑ ❑ ❑
E-scooter ❑ ❑ ❑
19. Are you a member of any car share program
(e.g., Colorado CarShare or Zipcar)?
❑ no ❑ yes
20. How many years have you lived in Boulder?
(Please write “0” if less than 6 months.)
Years
21. Are you a student at a university or a community college?
❑ no ❑ yes
22. What is your gender?
❑ man ❑ identify another way
❑ woman ❑ prefer not to say
23. Which category contains your age?
❑ 16 to 24 years old
❑ 25 to 34 years old
❑ 35 to 44 years old
❑ 45 to 54 years old
❑ 55 to 64 years old
❑ 65 years or older
❑ Prefer not to say
24. Are you of Hispanic, Latino, or Spanish origin?
❑ no ❑ yes
25. What is your race? (Mark one or more races to indicate
what race you consider yourself to be.)
❑ American Indian or Alaskan Native
❑ Asian
❑ Black or African American
❑ Native Hawaiian or Other Pacific Islander
❑ White
❑ A race not listed
❑ Prefer not to say
26. If you drive, what is the year, make and model of the
vehicle you usually drive?
Year:
Make:
Model:
Please email hagelinc@bouldercolorado.gov if you would like to receive
a summary of the results, once the study is complete.
Thank you very much for taking the time to
complete this survey. Please return this with your
travel diary in the postage-paid envelope provided