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4 - Recommendation on the use and delay-inducing traffic traffic calming devices for 17th St Bikelane Project CITY OF BOULDER TRANSPORTATION ADVISORY BOARD AGENDA ITEM MEETING DATE: November 25, 2002 Agenda Item Preparation Date: November 15, 2002 SUBJECT: Public hearing and consideration of a recommendation to City Council on the consideration of the use of delay-inducing traffic-calming devices as part of the 17th Street bike lane project design process. REQUESTING DEPARTMENTS: Public Works Department Tracy Winfree, Director of Public Works for Transportation Mike Sweeney, Transportation Planning and Operations Coordinator Bill Cowern, Transportation Operations Engineer Teresa Spears, Neighborhood Traffic Mitigation Program Liaison Fire Department Larry Donner, Fire Chief Steve Stolz, Deputy Fire Chief Police Department Mark Beckner, Police Chief Jim Hughs, Deputy Police Chief Tom Wickman, Commander of Police Traffic Unit BOARD ACTION REQUESTED: Staff requests a recommendation from the Transportation Advisory Board (TAB) on whether delay-inducing traffic-calming devices may be considered in the development of the 17`h street bikelane project. FISCAL IMPACT: To be determined throw h public in gut and the design process. PURPOSE: The purpose of this memorandum is to receive a recommendation from the Transportation Advisory Board (TAB) concerning whether city staff may consider the use of delay-inducing traffic-calming devices in the development of the proposed 17`h street project, which includes the Neighborhood Traffic Mitigation Program (NTMP) neighborhoods of Goss/Grove and Hillside. Recommendations from staff and the TAB will be forwarded to City Council for action. BACKGROUND The portion of 17th Street, from University Avenue to Walnut Avenue, was included in the 2001/2002 street overlay program. Due to roadway impacts and probable traffic diversion from the Broadway project, the overlay of this portion of 17`h Street was postponed until 2003. Agenda Item# When considering the overlay of 17'h Street and the resulting restriping of the street, staff identified that the Transportation Master Plan - Bicycle System Plan proposes bicycle lanes be added to 17`h Street, from Athens Street to Canyon Boulevard. To do so within the existing street width would require eliminating parking on one side of the street. In addition, the Goss/Grove neighborhood (17`h Street from Canyon Boulevard to Arapahoe Avenue) and the Hillside neighborhood (17`h street from Athens Street to where 17'h Street curves into University Avenue) are current participants in the NTMP. Sound judgment and fiscal responsibility dictates that an integrated planning approach be taken in considering the proposed bike lanes and the traffic mitigation request at the same time. The neighborhoods are already in the NTMP, and would be addressed as they rose in program priority. In 2000, a new set of guidelines was adopted for the NTMP. These guidelines provided a flow chart detailing the process by which a neighborhood would enter the NTMP as well as the order in which different mitigation methods and process steps would be taken. This flow chart is provided as Attachment A. The new guidelines placed more emphasis on public involvement and provided check-in-points with both TAB and City Council on decisions pertaining to the use of delay-inducing traffic-calming devices on Critical Emergency Response Routes (CERR) and non-CERR streets outside of the six-minute emergency response time zone. This portion of 17`h Street is a CERR. NTMP guidelines require that we obtain the TAB's recommendation and city council direction, regarding the potential consideration of the use of delay-inducing traffic-calming devices. PUBLIC PROCESS On Oct. 29, 2002, staff met with residents in the project area, including representatives from both the Hillside and the Goss/Grove neighborhood. To notify the public of the meeting, staff used a mailing list of approximately 700 property owners and residents along 17'h Street corridor. The meeting was also advertised on the Public Works Web site and announced in the Daily Camera. High traffic volumes, speeding traffic and the need for TMP-recommended bicycle facilities were discussed at this meeting. Residents in attendance unanimously agreed it was very important to be able to consider delay-inducing traffic-calming devices in the development of both of the neighborhoods' proposed traffic mitigation plans. In addition to the people who attended the meeting, staff received a-mails indicating support for the use of delay-inducing traffic mitigation devices in both the Goss/Grove and Hillside neighborhoods on 17`h Street. ANALYSIS Staff's analyses have shown that delay-inducing physical mitigation is more effective at reducing speeding traffic then non-delay inducing devices. The city of Boulder has a policy of trying to provide emergency response within six-minutes, utilizing roadways that are designated Critical Emergency Response Routes (CERR). The benefit of speed reduction on neighborhood streets must be weighed against the potential impacts to emergency response time. Attachment B Agenda Item# details the results of speed reduction and emergency response delay impacts for different traffic mitigation. STAFF RECOMMENDATION City staff from the Transportation Division, Fire Department and Police Department has considered the findings and the input from the community, and makes the following staff recommendation: • Delay-inducing, traffic-calming devices should not be considered as part of the neighborhood traffic mitigation plan on 17m Street in either the Hillside or the Goss/Grove neighborhood. NEXT STEPS The TAB recommendation on this issue will be forwarded to City Council. Staff will incorporate the results of City Council's action on this issue into the 17th Street Bike Lane project. Staff will continue to work with the Goss/Grove and Hillside neighborhoods by beginning the conceptual design process for the roadway, including proposed neighborhood mitigation and bicycle facilities. Staff will then follow the remaining steps of the NTMP policy, with the proposed plan, including the neighborhood polling process and a review for recommendation by the Transportation Advisory Board and review for approval by the City Council. ATTACHMENTS: A - NTMP Flow Chart B -Experimental Device Results - "How Did They Work" Agenda Item# You have a neighborhood traffic concern. Neighborhood Traffic Mitigation Program Process The NTMP sends you a ' "Neighbor to Neighbor Education Kit." Attachment A Education/Petition/Dat, Collection Phase Circulate petition for participation in the NTMP, due in April each year. - Concurrent application of educational tools (yard signs, speed monitoring trailers, 85th percentile speed o 5 mph over speed limit • Continue education efforts for another neighborhood speed watch, neighborhood speed pledge). 3 months. - Speed data collected T ` - 3 months) Remonitor traffic speeds. (timeframe ` Decision Point Decision Point "Revisit Problem No Problem" "Problem No Problem" 85th percentile speed > 5 mph over speed limit 85th percentile speed > 5 mph over speed limit NO ` Yes - initiate education and enforcement phase. Yes -transition to EducationlEnforcementphaw. No - continue educational efforts. No - continue educational efforts. YES YES NO Education/Enforcement Phase Continued application of educational tools. 85th percentile speed 16 mph over speed limit -Application of enforcement tools Continue education efforts. (photo radar and traditional officer speed-enforcement). - Additional speed data collected. - (timeframe - 6 months) T Decision Point "Eligibility for engineering treatments" 85th percentile speed 5 mph over speed limit 85th percentile speed > 5 mph over speed limit NO Continue education and enforcement efforts. Yes - continue education and enforcement and Remonitor traffic speeds as part of next annual include project in engineering ranking phase. process. No - continue educational and enforcement efforts. YES j Engineering Treatment Ranking Phase - All other projects continue education and , Neighborhood Needs Assessment Priority Checklist used to rank eligible projects. enforcement efforts. The two top priority projects - begin development of engineering treatment proposal _ rojects reranked annually. All other projects - continue educational and enforcement efforts. All Other Projects. 11wo Top Proorqty Proffiects (or More as staff and resources al s l Non-CERR Streets within 6-m'hute Response Time Zone CERR Streets and Non-CERR Streets outide 6-minute Response Time Zone Process Summary ( Process Summary - CEAP typically will not be required. Project streets evaluated on a case-by-case basis. Neighborhood public involvement process leading to project proposal. TAB provides recommendation to City Council on the use of delay-inducing devices. - Both delay-inducing and nondelay-inducing devices available. - CEAP may be required. Neighborhood ballot (residents and property owners) on proposal is final decision. Neighborhood public involvement process leading to project proposal. (timeframe - 6 months) Neighborhood ballot (residents and property owners) determine whether CEAP proceeds to City Council II (timeframe - 6 months) J i Final Decision Point Decision Point "Project Implementation" NO "Are Delay-inducing Devices Available?" -Neighborhood ballot (residents and property owners)' TAB recommendation to City Council. >=60% support -install improvements. N0 -initiate non-delay design process. Yes -initiate full design process. <60% support - don't. ?I YES , i NO YES _•-_-._m.,.___._ w - Non-delay Inducin esign Process Delay-inducing D sign Process Process Summary Process Summary Neighborhood public involvement process Neighborhood public involvement process leading to - Project not it lemented. Project Impl mented. leading to project proposal. project proposal. Neighborhood can reapply to the (timetrame - 3 months) I { - Neighborhood ballot (residents and -Both delay-inducing & nondelay-inducing devices NTMP in 3 Years. f homeowners) on proposal is decision-making available. continue education and process. T - CEAP required for delay-inducing devices. enforcement efforts. J I - -Neighborhood ballot (residents and property owners) on proposal determines whether proposal and associated CEAP proceeds. Neighborhood Ballot Area - ` Properties on or adjacent to the primary street proposed for an engineering treatment within 400 feet of either side of the proposed device and within 1 block on the side street Decision Point for intersection treatments (ex. traffic circles). For a cul-de-sac, the neighborhood ballot "Continue Project Consideration?" > area expands to include all properties from the treatment to the end of the cul-de-sac. NO Neighborhood ballot (residents and property owners) Neighborhood Ballot Voting Structure - >=60% support - continue project consideration.' One vote per dwelling unit and one vote per property owner. <60% support - don't. - Project not implemented. Neighborhood can reapply to the YES i NTMP in 3 Years. continue education and enforcement efforts. I I Final Decision Point "Final Project Consideration" NO TAB/City Council Consideration of Project CEAP With nondelay designs, step is eliminated. r~ Project Reassessment. YE5 (After 3 years.) Project Evaluation. Project Imp' ntedT >=60% support to remove - (After 1 year.) (timeframe - )nth,;) Device is removed. Attachment B APPENDIX D Experimental Device Results - "How Did They Work" SECTION PAGE(S) SECTION CI: SPEED HUMPS (INCLUDING STAGGERED SPEED HUMPS) Cl -C3 SECTION C2: RAISED CROSSINGS/FLAT-TOP SPEED HUMPS C4 - C6 SECTION C3: TRAFFIC CIRCLES (INCLUDING VOLCANO TRAFFIC CIRCLES)C7 - C15 SECTION C4: TRADITIONAL ENFORCEMENT STATISTICS C16 - C17 SECTION C5: 9TH STREET - SIGNAGE AND STRIPING STUDY C18-C19 SECTION C6: STOP SIGNS C20 - C27 SECTION C7: PHOTO RADAR SPEED ENFORCEMENT C28 - C31 SECTION C8: PHOTO RED LIGHT ENFORCEMENT C32 - C35 SECTION C9: SPEED SENSITIVE TRAFFIC SIGNALS C36 - C38 Data is current as of 1999 Originally produced as Attachment C of the 4/8/97 City Council Study Session Memorandum Revised for 3/30/99 TAB/City Council Joint Study Session SECTION Cl: SPEED HUMPS DESCRIPTION Speed humps are one of the more traditional neighborhood traffic mitigation devices. They require vehicles to slow down to avoid discomfort when driving over a physical hump in the roadway. Boulder's speed humps are generally 12 feet in length with a maximum height or peak of 4 inches. The installation of a speed hump and the subsequent signs and pavement markings costs approximately $1,000 per installation. Effectiveness at Speed Reduction Effectiveness depends upon the size of the hump and the spacing between devices. Data collected shows that the speed humps had a positive impact on speed reduction on the following streets. TABLE CI-1: Speed Data Comparison Before and After Speed Hump Installation I S (S l" ~ i Average S &tlr'e~cenfile Seed 11 MI. hge_ Bs~fizl er Chan"ge PialectStreeet Before t` Mapleton Ave (1500 block) 23 mph 21 mph -2 mph 28 mph 25 mph -3 mph North Street (1400 block) 27 mph 21 mph -6 mph 33 mph 25 mph -8 mph Floral Drive (2100 block) 27 mph 22 mph -5 mph 31 mph 25 mph -6 mph (Methods used to collect traffic data are not 100 percent accurate. There are enough daily fluctuations on roadway speed/volume and limitations in the technology used to collect the data that the information should be used for comparative purposes only. Eighty-fifth percentile speed is the speed at which 85 percent of the vehicles are traveling at or below that speed.) Public Input City staff has received many requests to place speed humps on neighborhood streets. Concern has also been expressed from other citizens that speed humps are dangerous to maneuver, cause unnecessary noise, degrade the beauty of their neighborhood and force vehicles to operate well below the speed limit.. SAFETY CONCERNS Accident trends Speed humps are generally used in the middle of city blocks, a good distance away from any intersections. Most accidents in the city occur at intersections. Therefore, it is unlikely that speed humps have much affect upon accident rates. Staff is not aware of any accidents which have been the result of any City of Boulder speed humps. Likewise, the accident rates for neighborhood streets where speed humps would be located are so low that it is not possible to evaluate any increase or decrease in accident rates with any degree of accuracy. Bicyclists and Pedestrians Bicyclists and pedestrians are not really impacted by speed humps. The one potential negative impact on bicycles is on roadways with bike lanes or paved shoulders. For drainage purposes, speed humps are sometimes constructed to slope down to the bottom of the curb. The slope generally occurs through the bike lane or shoulder which requires bicyclists to travel on an uneven surface. Emergency Response Delay occurs when an ambulance or fire engine passes over a speed hump. Staff has studied the effects of different speed hump sizes on emergency response. The results show that speed humps cause four to six seconds of delay per device. ENVIRONMENTAL CONCERNS The effects of slowing, stopping, idling and accelerating increase automobile exhaust, noise and fuel consumption. Vehicle Emissions The act of slowing and accelerating increases the amount of emissions put out by motor vehicles, Staff has not conducted any studies on the impact of speed humps on emissions. Noise The slowing and accelerating associated with any of the physical mitigation devices will result in localized noise impacts in the vicinity of the device. Fuel_ConiumptionfResource Impacts The deceleration and subsequent acceleration associated with speed humps probably increase gas consumption. PROGRAM RESTRICTIONS Diversion of Traffic to Adjacent Streets Staff has not studied most of the streets surrounding speed hump locations to see whether there was diversion associated with the placement of speed humps. See Table C1-2 for specific information on locations where a change in traffic volume as a result of speed hump installation were studied. TABLE CI-2: Changes in Traffic Volume Before and After Speed Hump Installations AVer'dgt'' Txla f1G' ° Cd4vF.h1Gle5;Ver .Street z+ r f $eore AffeF Oh.ngd vu~I'el'cent Alan e+ xi Mapleton Avenue (1500 block) 1,710 vpd 1,490 vpd -220 vpd 12.9% North Street (1400 block) 1,050 vpd 760 vpd -290 vpd -27.6% Floral Drive (2100 block) 900 vpd 670 vpd -230 vpd -25.6% 1998 Speed/Volume follow-up Traffic speeds and volumes were collected in 1998 on these three roadways where the speed humps remain. The results show that traffic volumes and speeds continue to be low on both North Street and Floral Drive. Both speeds and volumes increased on Mapleton Avenue but have not reached premitigation levels to date. For comparison purposes, the average speeds and 85th percentile speeds on Mapleton Avenue and Floral Drive were 22 mph and 27 mph, respectively, on both streets. The -Cl- average speed and 85th percentile speed on North Street was 21 mph and 26 mph. The traffic volumes on Mapleton Avenue, North Street and Floral Drive were approximately 1540 vpd, 520 vpd, and 570 vpd, respectively. Staggered Speed Hump Demonstration Staff planned a "staggered" speed hump design demonstration for fall 1998. Staggered speed humps are designed so that rather than having both approaches to the speed hump occur at the same location, they occur approximately 75 feet apart from each other. Thus, vehicles traveling on the roadway still must traverse the speed hump to stay in their lane but an emergency response vehicle could circumvent the speed humps be going into the opposing lane. The staggered speed humps were to be placed on Moorhead Avenue and Pennsylvania Avenue. However, a predemonstration survey of neighborhood opinions suggested that these demonstrations did not have support in either of these neighborhoods. As a result, the city's Transportation Advisory Board (TAB) conducted a public hearing on the proposed demonstrations and recommended to city staff that these demonstrations be canceled. Staff notified City Council of the decision to not go forward with the demonstrations through a October 14, 1998 Weekly Information Packet memorandum. -C2- SECTION C2: RAISED CROSSINGS/FLAT-TOP SPEED HUMPS DESCRIPTION Raised crossings are elongated versions of speed humps (essentially a large, flat-top speed hump). They require vehicles to slow down to avoid discomfort when driving over a physical hump in the roadway. The raised section is much longer and allows some of the longer vehicles (such as fire engines) to get both wheels up on the hump before the front wheel leaves the hump. Theoretically, this minimizes the potential for undercarriage damage when these types of vehicles travel over the humps. Boulder's raised crossings are generally 42 feet in length with a maximum height or peak of 6 inches. The installation of a raised crossing and the subsequent signs and pavement markings cost approximately $3,600 per installation if there are no drainage issues (which raise the cost considerably). EFFECTIVENESS AS A MITIGATION TOOL Sneed Reduction Staff has studied the effect of raised crossings as a speed mitigation device and found them to be effective at reducing speeds. The level of effectiveness depends upon the size of the device and upon the spacing between devices. TABLE C2-1: Speed Data Comparison Before and After Raised Crossing Installation 1 Et i T AVCr1g*"' r rSip1,UCTGeItIjS3eeti k2 Pxolect Streei Before,SI1er Changd, fBeforeAfter'y Change Moorhead Avenue (3100 block) 29 mph 27 mph -2 mph 34 mph 31 mph -3 mph Moorhead Avenue (4300 block) 28 mph 27 mph -1 mph 34 mph 31 mph -3 mph Edgewood Drive (2200 block) 29 mph 24 mph -5 mph 36 mph 28 mph -8 mph (Methods used to collect traffic data are not 100 percent accurate, There are enough daily fluctuations on roadway speed/volume and limitations in the technology used to collect the data that the information should be used for comparative purposes only.) 1998 Speed data follow-up No follow-up to these locations was conducted. The raised crossing mitigation devices on Moorhead Avenue and Edgewood Drive have been removed. Public lnput City staff has received many requests to place raised crossings on neighborhood streets. Concern has been expressed from other citizens that raised crossings are dangerous to maneuver, cause unnecessary noise, degrade the beauty of the neighborhood and force vehicles to operate well below the speed limit. SAFETY CONCERNS Accident trends See comments for speed humps, Section C 1. -C3- Bicyclists and Pedestrian s See comments for speed humps, Section C 1. Emergency Response As with speed humps, staff test results show that raised crossings cause between four and six seconds of delay per device. The purpose of developing the raised crossing was to decrease the negative impacts on fire engines. Experience and comment from the Fire Department suggest that this is not a significant benefit and probably does not justify the additional cost. ENVIRONMENTAL CONCERNS See comments for speed humps, Section C1. PROGRAM RESTRICTIONS Diversion of traffic to adjacent streets In 1996, staff studied the most logical adjacent streets at both raised crossing locations to see whether there was diversion associated with the placement of speed humps. On Martin Drive, adjacent to Moorhead, no mitigation was placed to offset potential diversion. On Floral Drive, adjacent to Edgewood, the city constructed three speed humps to handle existing speeding issues and to offset potential diversion. The potential for traffic diversion from the Edgewood raised crossings was also studied on Glenwood Avenue which is parallel to but several blocks north of Edgewood. TABLE C2-2: Traffic Volume Before and After Raised Crossing }Installation - Martin Acres ZIH "ag £ i t 3^ f is 4' LI31ktt s ' .NI t i a t t t T 113 g c Stz~t , $eore Affe Cihauge ;'eicenf;Cange -4v 0, . , . Moorhead Avenue (3100 block) 4,590 vpd 4,460 vpd 130 vpd -2.8% Moorhead Avenue (4300 block) 2,810 vpd 2,620 vpd 190 vpd -6.8% Martin Drive (3 100 block) 930 vpd 990 vpd 60 vpd +6.5% Martin Drive (4300 block) 670 vpd 630 vpd 40 vpd -6.0% These results suggest that the raised crossings did not divert a significant amount of traffic to Martin Drive and may have diverted some traffic onto U.S. 36. TABLE C2-3: Traffic Volume Before and After Raised Crossing Installation - Edgewood/Floral sue. t 4 { ' ( ~Y'~?etage, DtFj?f:~ 1~IA1r1G'~ { t,{ § st c r StreCt { *d a r a F„Bef£YIe < A"IICL t st u IIteYeeTSt ClraflgPro- Edgewood Drive 11,140 vpd 9,690 vpd 1,450 vpd -13.0% Floral Drive 900 vpd 670 vpd 230 vpd -25.6% Glenwood Drive 490 vpd 480 vpd 10 vpd -2.0% -C4- The reduction on Floral is likely to be due to the speed humps there, rather than the raised crossings on Edgewood. These results suggest that the raised crossings did not divert a significant amount of traffic to Floral Drive or Glenwood Drive and may have diverted some traffic onto Iris Avenue. 1998 volume follow-up study No follow-up to these locations was conducted. The raised crossing mitigation devices on Moorhead Avenue and Edgewood Drive have been removed. -C5- Section C3: TRAFFIC CIRCLES DESCRIPTION Traffic circles rely upon a change in traffic control and a physical feature which vehicles must maneuver around to slow their speed. Since January 1995, all traffic circle locations in Boulder have all-way yield traffic control (prior to that time, STOP signs on the side street controlled traffic). This all-way yield condition requires vehicles to yield to traffic which is already in the circle but does not require them to stop if there is no conflicting traffic. The traffic circles are typically 20 to 25 feet in diameter and slow vehicles to between 15 mph and 20 mph when they are passing through them. The installation of a traffic circle with the appropriate traffic control costs approximately $10,000 to $40,000 per intersection. The Transportation Division has constructed six permanent small diameter traffic circles, temporary or permanent, in order to reduce vehicle speeds. The locations studied are: • Pearl Street & Fourth Street (1983) • Pearl Street & Third Street (1983) • Ninth Street & Evergreen Avenue (1994) • Arapahoe Avenue & Fourth Street (1995) • Arapahoe Avenue & Fifth Street (1995) • Sixth Street & Maxwell Avenue (1995) Two other larger diameter traffic circles were built as part of new developments. These circles were installed during subdivision construction more as traffic control devices than as speed mitigation devices. As such, no "before" traffic data exists. The circles in the Four Mile Subdivision and the Noble Park Subdivision are not part of this study. BACKGROUND In August 1995, the city installed trial traffic circles on Pine Street at 15th and 17th Streets, and on Balsam Avenue at 14th and 15th Streets. Both Pine and Balsam are major streets, primary bicycle corridors and primary emergency response routes. All four trial circles were constructed with a simulated standard curb-edge. EFFECTIVENESS AS A MITIGATION TOOL Sneed Reduction Traffic circles were placed on North Ninth Street, Arapahoe Avenue, Balsam Avenue and Pine Street to mitigate traffic impacts. City staff has studied the effect of these traffic circles as a speed mitigation device and found that they were effective at reducing speeds at every location. Speeds were measured midblock between paired devices to gauge their overall impact. -C6- TABLE C3-1: Traffic Volume Comparison on Project Streets i 4_ _ r ~"a'" - 3 Aerage'T)a11y ~rath+f: F" a F x_ h t A~ * { t t ~ F~ h~ hu.i i } l ~ PSQ.(t'.y6t StCe F er e G.hatt e t g i~ < * . Before ' r tNl u UChange. North Ninth Street (n/o Evergreen) 3,360 vpd 1,970 vpd -1390 vpd -41.4% Arapahoe Ave (400 block) 2,010 vpd 1,940 vpd -70 vpd -3.5% Balsam Ave (140011500 block) 10,910 vpd 8,280 vpd -2630 vpd -24.1% Pine Street (1600 block) 8,660 vpd 7,280 vpd -1380 vpd -15.9% Table C3-2 shows the change in traffic speed before and after the same conditions. The speed data shown includes the average speed and the 85th percentile speed. TABLE C3-2: Traffic Speed Comparison on Project Streets P4v~rage Steed ' 1. E $klt Pewetttrl~ Speed "t' Project Street efQie Aftez l a e $ $eftare tfler Ghar~g6 North Ninth St (n/o 28 mph 20 mph -8 mph 33 mph 23 mph -10 mph Evergreen) Arapahoe Ave (400 block) 28 mph 26 mph -2 mph 33 mph 28 mph -5 mph Balsam Ave (140011500 blk) 31 mph 23 mph -8 mph 38 mph 25 mph -13 mph Pine Street (1600 block) 30 mph 25 mph -5 mph 33 mph 31 mph -2 mph (Methods used to collect traffic data (speed 8 volume) are not 100 percent accurate. There are enough daily fluctuations on roadway speed/volume and limitations in the technology used to collect the data that the information should be used for comparative purposes only.) The data for North Ninth Street involves a comprehensive mitigation project which included four-way stop control at Ninth and Balsam, a median treatment just north of that intersection, and the traffic circle at Ninth and Evergreen. It is likely that all three of these devices had something to do with the change in traffic speeds and volume on the roadway. 1998 Speed/Volume follow up Traffic speeds and volumes were collected in 1998 on Balsam Avenue between the two temporary traffic circles. The data suggests that while travel speeds remain low (23 mph average speed, 26 mph 85th percentile speed), traffic volume has increased. Prior to the traffic circles being placed at these locations, the traffic volume was approximately 10,910 vpd. Following the placement of the circles, the volume dropped to approximately 8,280 vpd. Two years later, the traffic volumes have increased to approximately 9,570 vpd on this section of Balsam Avenue. 1998 speed and volume data were also collected on Alpine Avenue. This roadway is adjacent to Balsam Avenue and saw the largest increase in traffic when the traffic circles were placed. -C7- Prior to the traffic circles being placed on Balsam Avenue, the traffic volume on Alpine Avenue was approximately 2,610 vpd. Following the placement of the circles, the volume increased to approximately 3,230 vpd. Two years later, the traffic volumes have increased to approximately 3,440 vpd on this section of Alpine Avenue. Public Innut City staff has received many comments about traffic circles. Public comment has centered on the experimental circles on Pine and Balsam. Very few comments have been made about other permanent traffic circles. Several people have called in support of the devices. Far more people have called to say they do not like the devices and/or feel the devices are confusing or unsafe. In particular, there seems to be confusion over who has the right-of-way in the intersection and there is concern about safety for bicyclists and pedestrians. GO Boulder's Close-call Hotline has recorded many of these safety concerns. SAFETY CONCERNS Accident trends Traffic circles have been used in other cities and countries as a safety device to mitigate locations with a high number of right angle collisions. The safety research is divided when it comes to pedestrians and cyclists. Some studies indicate that bicyclist-vehicular accidents tend to rise at traffic circles due to the failure of motorists to yield to circulating bicyclists. In addition, while slower traffic may make midblock pedestrian crossing safer, traffic circles may also make it more difficult for pedestrians to cross at the intersections themselves. Staff has reviewed the accident history at all permanent and temporary traffic circle locations in the city between January 1992 and December 1996. Each accident report in this time period at a traffic circle location was reviewed to see if the accidents occurred in the intersection or were caused by actions in the intersection, and to determine whether there are any trends. Staff also reviewed whether accident rates have increased or decreased at traffic circle locations before and after circle construction and whether accident rates have increased or decreased after side street STOP sign control was replaced with all-way YIELD signs. Permanent Traffic Circle Locations (through 1996) The permanent locations which were in place during the study time period (1992 to 1996) do not show a high number of accidents. The intersection of Fourth and Pearl showed a slight increase in accident rate after the traffic control was changed from side street stop control to all-way yield control. Those permanent locations which were installed sometime during the study time period generally showed either a lower number of accidents per year after installation of the traffic circles or no increase in accidents at all. However, these locations had very low accident numbers to begin with. Temporary Traffic Circle Locations (through 1996) The intersection of 14th/Balsam had three accidents, including two serious injury accidents during the three and one-half years prior to the installation of the traffic circle. Two of the accidents involved -Cg- speeding vehicles on Balsam Avenue. No accidents occurred at this location after the installation of the traffic circle. The 1 5th/Balsam intersection had no accidents during the three and one-half years prior to the installation of the traffic circle and one accident during the one and one-half years after the installation. This accident involved a driver who claimed to have sun in his eyes and drove directly through the traffic circle causing considerable damage to his car and to the traffic circle but no injury to himself or anyone else. The 15th/Pine intersection had seven accidents (four injury accidents) during the three and one-half years prior to the installation of the traffic circle, and four accidents (no injury accidents) during the year and one-half after installation. Most of the accidents which occurred prior to the installation of the traffic circle involved speeding traffic on Pine Street, usually with injuries. Three of the four accidents which occurred after the installation of the traffic circle involved ice and snowy weather as contributing factors. All accidents were low speed collisions and did not involve any injuries. The 17th/Pine intersection had nine accidents (five injury accidents) during the three and one-half years prior to the installation of the traffic circle, and seven accidents (two injury accidents) during the year and one-half after installation. Most of the accidents which occurred prior to the installation of the traffic circle involved speeding traffic on Pine Street, usually with injuries. All of the accidents which occurred after the installation of the traffic circle involved ice and snowy weather as contributing factors. All of the accidents were low speed collisions and most did not involve injuries. The two accidents with injuries were relatively minor. The accident information at the temporary traffic circles suggest that the probability of accidents occurring on the two different streets is very different. Balsam Avenue has had very few accidents prior to the installation of the traffic circles and even fewer after the circles. Pine Street had many more accidents than Balsam Avenue prior to the circles and saw a marked increase in accidents after the installation of the traffic circles. Other factors noted was that almost all of the accidents which occurred at the Pine Street traffic circles had icy/snowy weather as a contributing factor and that the severity of accidents at the two intersections dropped considerably. Both Balsam Avenue and Pine Street are plowed as secondary snow routes. A change in traffic control (such as the replacement of side street STOP signs with all-way yield signs) which removes the right-of-way from main street traffic typically increases the number of accidents at an intersection. One well-researched fact of automobile travel is that when vehicles are constantly changing speeds (or in this case, slowing to a stop and then proceeding again), they are more likely to get in an accident than when they are traveling at a constant speed. Staff makes traffic control changes when they believe that severe accidents, which often result in major injuries, can be avoided or when such changes would result in conditions to reduce speeds and reduce the chance of accidents with injuries. Table C3-3 details the number of accidents at each location studied over the four-year time period. Accidents per year are shown with injury accidents in parentheses. Accidents which occurred while a traffic circle was in place are shown with a following the number. -C9- TABLE C3-3: Number of Accidents at Traffic Circle Intersections "AA z ' - _ ~s e R'~ .Z..t s sF 7'?i ~t~ { inY~ ai"t-7 qis PF''t 3 .Loeaftort Pearl & Third 0 0 0 0 0 Pearl & Fourth 1 * 1 * 0 1 It 2* Arapahoe & Fourth 0 0 0 0 0 Arapahoe & Fifth 0 0 0 0 1 Sixth & Maxwell 0 1 1 0 0 Ninth & Evergreen 2 0 2 0 0 Balsam & 14th 1 0 2(2) 0 0 Balsam & 15th 0 0 0 1* 0 Pine & 15th 2(1) 2(1) 2(1) 1(1) 4* Pine & 17th 2(2) 2(1) 4(2) 1 8(2)* A look at the total number of accidents can be somewhat deceptive. A more appropriate measure of the relative safety of an intersection is to look at the number of accidents which occur at an intersection versus the amount of traffic that moves through the intersection. Traffic engineers measure this accident rate in "accidents per million entering vehicles." The city studies such accident rates in the "Hazard Elimination Program (HEP)" and generally considers an intersection to have a "high" accident rate if it is higher than 2.0 accidents per million entering vehicles. The top 10 intersections on the 1996 HEP report were all higher than 1.9 accidents per million entering vehicles. TABLE C3-4: Accident Rates tnt rsecrion f a11y Trz fie Entering P g na Acctde~tspet, l n Acerdn mil F (9t9CL d3{a) _@t.C`(*~',f # CEl erln 'YCh1C~~S ; Balsam & 14th 8,100 vpd 0 0.0 Balsam & 15th 8,400 vpd 1 0.2 Pine & 15th 9,090 vpd 4 0.9 Pine & 17th 8,630 vpd 8 1.8 * - trial period of 16.5 months (502 days) A review of the accident rate data shows that the intersection of 17th/Pine has a relatively high accident rate for a residential intersection. A rate of 1.8 accidents per million entering vehicles would probably put this intersection in the top 30 intersections in the city. The other three intersections have low accident rates. -C10- 1998 Accident information follow up A review of accident records for 1997 and 1998 show that the total number of accidents and the severity of accidents remained low for all traffic circle locations. There were no intersections with more than two accidents per year and most intersections had one or less accidents per year. The intersection of Pine Street and 17th Street showed the greatest improvement with only three accidents occurring in the two year time period. Another significant fact observed was that since the construction of the traffic circle on Ninth Street and Evergreen Avenue, almost five years ago, there has not been a single accident at this location. Compliance For the traffic circles to operate, motorists must comply with the traffic control which requires them to yield to traffic already in the traffic circle. Staff has made observations at several traffic circles but has not collected any specific compliance data. Our observations suggest that compliance is still an issue but there appears to be higher compliance in 1998 than when the traffic circles were first installed. Compliance also seemed to be higher at intersections where the main street volume was lower or where the main street and side street traffic volumes were similar. The design of the traffic circle itself also seemed to have an effect on compliance level with the bigger traffic circles having better compliance than the smaller circles. Bicyclists and Pedestrians Traffic circles are not considered to be beneficial for either bicyclists or pedestrians. The traffic circles are designed with a narrow approach which forces vehicles to slow down as they enter. This narrow approach also requires bicyclists to merge with motor vehicle traffic traveling in their direction. Signage near the experimental traffic circles on Pine Street and Balsam Avenue warns vehicles to not pass bicyclists through the traffic circle. Field observations have shown that compliance with this request is generally good though bicyclists have called to complain that they do not feel safe in the traffic circles. Traffic circles on roadways which are designated bicycle facilities may discourage bicyclists from riding on these roadways. Pedestrians crossing at traffic circles are likely receiving little benefit. Traffic circle themselves may obscure pedestrians who are crossing at the intersection, and this may serve as a deterrent for pedestrians. Some pedestrians have called to complain that they do not feel safe crossing near the traffic circles. On the other hand, slower auto speeds which have been measured are likely making it somewhat easier for pedestrians to cross the main street, particularly in the mid-block. Emergency Response Delay is experienced whenever an ambulance or fire engine must pass through an intersection where they do not have the right-of-way. Traffic circles cause more delay by forcing the fire truck to maneuver through a constrained area. Tests done by Transportation Division and Fire Department staff show that traffic circles cause 7.5 to 10 seconds of delay per device. Also, the banking movement required of fire trucks as they pass through the traffic circles may cause damage to the vehicle itself. In addition to the cost of repairing the vehicle, the time spent fixing the vehicle may cause a further impact on emergency response if other vehicles are not available to cover the service that vehicle was providing. -C11- ENVIRONMENTAL CONCERNS See comments for speed humps, Section C 1. PROGRAM RESTRICTIONS Diversion of Traffic to adjacent streets Staff has looked carefully at the potential diversion associated with the placement of traffic circles. When the permanent circles were placed at Ninth/Evergreen and the two Arapahoe traffic circles, staff conducted before and after data collection to monitor speed and volume. Surrounding roadways of a similar or lesser classification did not experience an increase in traffic volume or speed in the vicinity of the Ninth/Evergreen traffic circle, despite the fact that the total volume on Ninth Street in the vicinity of the traffic circle decreased significantly. The missing traffic was most likely diverted onto Broadway. Following the construction of the Arapahoe traffic circles, there was an increase in traffic on Marine Street. The traffic volume on Marine Street was low to begin with and the increase in traffic was small. Speeding was not a problem on this street before or after the installation of the traffic circle. Staff also monitored the potential for traffic displacement with the construction of the temporary traffic circles on Balsam Avenue and Pine Street. When the traffic circles were installed on Balsam Avenue, traffic volumes increased on Elder Avenue, Cedar Avenue and Alpine Avenue (all lower classification streets). The increase on Alpine Avenue may be more closely associated with the placement of speed humps on North Street. Mitigation on both Elder Avenue and Cedar Avenue (the placement of four-way stop control at three intersections) did little to reduce speeds and had no impact on volume on the two streets. No mitigation has been attempted on Alpine Avenue due to emergency response concerns. When the traffic circles were installed on Pine Street, traffic volumes on Mapleton Avenue stayed about the same and the speed went down slightly. Spruce Street actually had different speed and volume characteristics between different blocks. In the 1700 block, the volume increased considerably but the speeds decreased. In the 2200 block, the volumes did not increase as much but the speeds did not decrease as much either. TABLE C3-5: Changes in Traffic Volume on Adjacent Streets ~U3~Sat11 A etft B yBefare' ~k$e~i ttng 1a Change ; Elder Ave. 1,580 vpd 1,730 vpd +150 +9.5% Cedar Ave. 560 vpd 750 vpd +190 +33.9% Alpine Ave. 2,610 vpd 3,230 vpd +620 +23.8% t t t :i 3. u: r Fz 4r, i. .:3 ~ 'y r2`~=.°•`k~€ lv~j~i~ PiRtree 1tig~UOIT , d 3 F BeOte er t' l~Itk*t t o G t _ ice= Mapleton Ave. 1,420 vpd 1,490 vpd +50 +49% Spruce St. (2200 block) 3,830 vpd 4,040 vpd +210 +5.5% -C12- I Spruce St. (1700 block) 3,040 vpd 3,720 vpd +680 +22.4% (Methods used to collect traffic data are not 100 percent accurate. There are enough daily fluctuations on roadway speed/volume and limitations in the technology used to collect the data that the information should be used for comparative purposes only.) Table C3-6 shows the change in traffic speed before and after the same conditions. The speed data shown includes the average speed and the 85th percentile speed. TABLE C3-6: Changes in Traffic Speed on Adjacent Streets Average speed 85th Percentile Speed P -A e Aft, Change .Balsam AveaMthgattoiiefire". After ` Cltange Beoi Elder Ave. 27 mph 26 mph -1 mph 33 mph 31 mph -2 mph Cedar Ave. 26 mph 23 mph -3 mph 33 mph 28 mph -5 mph Alpine Ave. 31 mph 28 mph -3 mph 38 mph 34 mph -4 mph Pit?e 8treetMiflgat}oti' , el`vre After Change liefo e ' #1ft r Change 1 25 mph 21 mph -4 mph 28 mph 25 mph -3 mph Mapleton Ave. Spruce St. (2200 block) 31 mph 29 mph -2 mph 38 mph 37 mph -1 mph Spruce St. (1700 block) 27 mph 24 mph -3 mph 33 mph 28 mph -5 mph OTHER CONSIDERATIONS Community Concems/City Policies Traffic circles have existed in Boulder for years, but the experimental traffic circles on Pine and Balsam introduced the concept to a large number of drivers. They are not common in most communities, and therefore they can be confusing to the public. In addition, when the traffic circles were installed, our Code did not take into account the fact that it is extremely difficult to signal a vehicle's intention to make a left turn when entering a traffic circle because the vehicle must turn to the right to maneuver through the traffic circle first. The Transportation Division worked with the City Attorney's office to develop an Ordinance change which would make it legal for vehicles to turn left from a traffic circle without having to signal. This is consistent with the concept that a vehicle must yield to any other vehicle in the traffic circle regardless of the movement they are making. The high number of accidents at the Pine Street intersections suggest that traffic circles at intersections with high traffic volumes, reasonable side street volumes and snow may be problematic. Some thought should go into the impact upon the city's street maintenance resources if many traffic circles are added. It should be noted that the 1997 and 1998 accident data showed considerably fewer accidents at the two Pine Street locations. Traffic circles require vehicles to slow below the speed limit to maneuver through them. While this impact is relatively small (a reduction of five to 10 mph) compared to other devices (such as STOP signs), it is still an issue to be considered. The goal of the NTMP is to get traffic in neighborhoods to drive the speed limit or close to it. On every street in the NTMP there are drivers who are already -C13- complying with this goal and driving no faster than the speed limit. Such drivers would suffer the same inconvenience as drivers who are currently speeding. TIDE MODIFIED DESIGN OR "VOLCANO "TRAFFIC CIRCLE TEST• Design Objective The original trial traffic circles were built with 6-inch high bumper blocks to simulate a standard curb- edge perimeter. This design forces all vehicles, including emergency response vehicles, to travel around the circle to pass through the intersection, thus reducing vehicle speed. The required "turning" maneuver results in an additional 7.5 to 10 second/circle delay for emergency vehicles. Staff proposed a "volcano," or conical-shaped traffic circle, featuring a low-profile, mountable edge for further testing. The modified edge design would need to be shallow enough to allow emergency response vehicles to travel over the rim of the circle in a straighter path through the intersection. It was anticipated that this would result in less delay for these vehicles at each traffic circle. At the same time, the modified edge would have to be formidable enough to discourage other vehicles from traveling over the circle edge. Should this happen, it would defeat the overall objective of using a traffic circle to achieve speed mitigation. Initial Test at the City Yards A test run with City emergency response vehicles and a "volcano" circle was conducted at the City Yards on October 14, 1996. The volcano circle design was based on a design used in Portland, Ore. Staff constructed a full circle with a 4-to-1 slope and alternative edge heights of two and three inches (on each hemisphere). The altering edge depths were provided to determine which edge height had the least impact on response vehicles, and which, if either, would be preferable to Fire Department personnel. Pending Fire Department approval, the second phase of the experiment would entail on-site construction of three volcano circles on Pine at the intersections of 19th, 22nd and 24th streets for sustained testing. During the initial test phase at the City Yards, Fire Department personnel were not able to traverse the edge of the (lower) two- inch high circle perimeter at a speed sufficient to achieve less delay than now experienced with the standard curb-edged trial circles. Fearing damage to the vehicle, drivers felt compelled to come to an almost complete stop before mounting the rim of the circle. Findings Staff concluded that the trial volcano circle would have a greater negative impact on emergency response time, if used as intended. A volcano circle design would likely equal the delay experienced with existing designs, if drivers chose to drive around, not over, the perimeter. Since the original objective with using a modified design was to achieve less delay at each traffic circle, staff determined that trial volcano circles should be constructed. -C14- SECTION C4: TRADITIONAL ENFORCEMENT BACKGROUND In 1996, staff considered the neighborhoods that had applied to the NTMP and developed a list of High Enforcement Zones (HEZ) for the Police to focus their speed enforcement efforts upon. At the time of this study, there were approximately 38 designated HEZ areas on 30 individual streets identified on the NTMP/ Critical Emergency Response Route (CERR) map. In the summer of 1996, traffic unit personnel began rotating through this number of streets with peak period enforcement by four officers three days per week and two officers two days per week. This resulted in an individual HEZ street segment receiving full enforcement (all four available personnel) on a Tuesday and Thursday of a week, followed by full enforcement on Wednesday of the following week. Within a 10 to I 1 week cycle, all of the HEZs received two days of enforcement, and six HEZ streets/segments received four days of "saturated" enforcement. Using this schedule, it would have taken over a year before a street rotated all the way through the cycle to get four days of saturated enforcement again. HEZ EXPERIMENT To measure the affects of the HEZ, baseline speed and volume data was collected on two streets prior to the two week HEZ enforcement described above. (Example: three days of enforcement the first week and two days the second week). The two streets selected were Baseline Road and N. 26th Street. TABLE C4-1: Autos Speeds Before and After Hez Enforcement (Using 85th Percentile Speeds) 57 ' t Street ~d~?' ~ ' ~~eeks' ~ 41t1ee~`" a Speed3efort tHEI" Af1erFTFZ Afe[IE t Street w Limsi, Eztfaremenf'nfotrxri~ent enforcement N. 26th St (Between Iris & Kalmia) 25 34 mph 34 mph 37 mph N. 26th St (Between Norwood & Agate) 25 37 mph 34 mph 37 mph Baseline (Between 13th and 14th) 30 34 mph 37 mph 34 mph Baseline (Between Grant & Eighth) 30 37 mph 34 mph 37 mph TABLE C4-2: Percent of Autos Speeding Before and after HEZ Enforcement A- r J ~ ,ro r Sheet vt;' dtng oi 4 ker l3 after HEZ of Street LuntL : IIEZ Enforceriient nfarcetxtettn"force~nenr N. 26th St (Iris to Kalmia) 25 74% 72% 85% N. 26th St (Norwood to Agate) 25 78% 72% 78% Baseline (Between 13th and 14th) 30 42% 77% 57% Baseline (Between Grant & 30 67% 58% 62% Eighth) -C15- The results for this demonstration are somewhat inconclusive. Two weeks following the enforcement, the speeds were down in some locations, and the same or higher in others. After four weeks, all speeds returned to their previous level or higher. This level of enforcement does not appear to be effective as a speed mitigation device. Traditional Enforcement Cost In 1998, the NTMP staff working group attempted to model how many officers would be required to perform speed enforcement on all NTMP streets which were also Critical Emergency Response Route (CERR) streets at a level of enforcement which would likely impact corridor speeds. Several assumptions were made concerning how many enforcement officers would be needed to accomplish this task and how frequently each street would need to be enforced. Based upon this model, there would need to be an additional 70 to 117 commissioned traffic officers hired to perform this task. Costs associated with this approach would include salaries for the new officers, equipment (weapons, vehicles, radar, etc...) and the need to expand the current Public Safety Building to accommodate the new officers. This would result in a one-time cost of between $2.8 million and $4.26 million. There would also be an on-going yearly cost of between $4.24 million and $8.1 million. In addition, there would be impacts to both the Courts and the City Attorney's office. It is anticipated that there work load would be increased by approximately six times it's current level. There would need to be additional clerks, judges and attorneys hired to accommodate this workload. The on-going yearly cost of these additional employees would be between $3.5 million and $4.0 million. Another cost consideration would be the construction of a new facility to accommodate these new employees. There would need to be at least five more courtrooms to handle the court cases and would be approximately 65,000 square feet in size. It is unlikely that this additional space could be accommodated at the current facility, so a new facility would have to be constructed at a different location. This would likely cost an additional $10 million to $15 million depending upon where it was located. It may be possible to renovate an existing 65,000 square foot building, if a suitable location could be found. This would reduce the cost. In summary, it appears that this approach would cost the city between $12 million and $20 million in up-front costs, plus an additional $7.5 million to $12 million in on-going yearly costs. One possible funding mechanism for this effort would be a significant increase in the fines for speeding within the City of Boulder. Based on the aforementioned officer projections, it is anticipated that they could generate approximately 70,000 to 100,000 speeding citations per year. To fund the annual costs of the aforementioned effort, this would result in an increase in fines of between $110 and $120. The flaw in this approach, however, is that as enforcement officers generated this number of citations, there would likely be a significant decrease in speeding (which is the goal of this effort). Less speeding would mean fewer citations, and this funding source would likewise decrease. -C16- SECTION C5: NINTH STREET - SIGNAGE AND STRIPING STUDY DESCRIPTION Passive mitigation involves using devices such as signs and pavement markings to encourage traffic to slow down. They do not physically constrain or impact vehicles on the roadway. Passive mitigation could include speed limit signs or crosswalk markings. It can also include signs asking vehicles to slow down, drive the speed limit, watch for children, etc. The city has used these devices sporadically throughout the city at several resident requests. In 1996, the city studied one such corridor (Ninth Street between Pine and Mapleton) to assess the effectiveness of such devices when used for speed mitigation. The installation of passive mitigation is variable depending upon what type is chosen. Signs are typically $200 per installation. Crosswalks and other pavement markings are between $200 and $500 per installation. EFFECTIVENESS AS A MITIGATION TOOL Speed Reduction Staff has studied the effect of "passive mitigation" on the Ninth Street corridor between Spruce and Mapleton. The devices were relatively ineffective at reducing speed. These results are consistent with feedback we have received from the public concerning signs and pavement markings and their confidence in those devices as speed mitigation. City staff has collected speed data on Ninth Street, between Pine and Mapleton before and after the installation of additional speed limit signs and then again after the installation of crosswalks as well as speed limit signs. Table C5-1 outlines the results of the before and after speed data study. TABLE C5-1: Speed Data Comparison Before and after Passive Mitigation i s Average Speed .e i_. h aA t e t1Ie5 efl i P, 'kv PFO'ect SCreeiJ Before-; -Aflei: Change :Befsrxe tex Change€, Ninth Street (Pine to 28 mph 28 mph 0 mph 32 mph 31 mph -1 mph Mapleton) (Methods used to collect traffic data are not 100 percent accurate. There are enough daily fluctuations on roadway speed/volume and limitations in the technology used to collect the data that the information should be used for comparative purposes only.) IMPACTS SAFETY CONCERNS Accident trends Passive mitigation does not provide any type of physical obstacle to drivers. Therefore, it is unlikely that it has much affect upon accident rates in a corridor. Staff is not aware of any accidents which have been the result of "passive mitigation." Bicyclists and Pedestrians Passive mitigation has little to no impact to bicyclists and pedestrians. -C17- Emergency Response Passive mitigation has little to no impact on emergency response. ENVIRONMENTAL CONCERNS The use of different mitigation treatments have several environmental/quality of life issues associated with them. Specifically, the effects of slowing, stopping, idling and accelerating increase automobile exhaust, noise and fuel consumption. Vehicle Emissions Since "passive mitigation" does not result in a significant slowing or stopping of traffic, it is not likely that it has a significant impact on vehicle emissions. Noise Since "passive mitigation" does not result in a significant slowing or stopping of traffic, it is not likely that it has a significant impact on noise in the corridor. Noise is directly linked to traffic speed. Fuel Consumption/Resource Impacts Since "passive mitigation" does not result in a significant slowing or stopping of traffic, it is not likely that it has a significant impact on vehicular fuel consumption. PROGRAM RESTRICTIONS Diversion of traffic to adjacent streets Since "passive mitigation" was so ineffective as a speed mitigation device, it is not likely that it caused significant diversion of traffic to side streets. The corridor chosen for study did not see a significant change in traffic volume. OTHER CONSIDERATIONS Public Input City staff receives many requests to place signs and/or crosswalks requesting slower or more cautious behavior from drivers. Staff has also received feedback in areas where these devices have been used to suggest that they are not very effective and do not satisfy the concerns of the neighborhood concerning speed mitigation, Community Concerns/City Policies Staff has concerns about the proliferation of signs and pavement markings throughout our city's roadways. Initial installation costs are low but yearly maintenance is expensive (particularly for pavement markings which are maintained every few years). In addition, this type of sign/marking `pollution" can detract from. other important messages which staff is trying to convey to the driving public. To date, there are over 6,000 signs placed throughout Boulder. -C18- SECTION C6: STOP SIGNS DESCRIPTION STOP signs are regulatory devices used by the city to assign right-of-way. The installation of two additional STOP signs at an intersection costs approximately $200 per intersection. The addition of two STOP bars (pavement markings) to clarify the stopping location, costs an additional $300 per intersection. EFFECTIVENESS AS A MITIGATION TOOL. Sneed Reduction Transportation engineers have debated the effectiveness of STOP signs as speed control for many years. Considerable research into this area has been done in other jurisdictions. In 1992, the City of Portland, Ore., performed an extensive evaluation of their STOP sign installation warrants. As part of that evaluation, the city looked at the effectiveness of STOP signs as speed mitigation when they were placed at locations which would not typically be considered for STOP sign control. It found that the use of multi-way stop control MAY result in a decrease in vehicle speeds. However, there were a sufficient number of negative tradeoffs (poor compliance, increased accident rates, etc.) that the City of Portland did not recommend using STOP signs as speed control devices. The City of Pueblo, Colo., recently studied the effects of STOP signs as speed control devices on several of their intersections. The results showed that vehicle speeds were slower within 150 feet of the STOP signs, but after that, vehicle speeds went up to the same speeds as before or higher. This lack of effectiveness, coupled with poor compliance at the STOP signs, resulted in the City of Pueblo concluding that STOP signs were not an effective or appropriate speed mitigation tool. City of Boulder staff have studied the effect of STOP signs as a speed mitigation device and found that they can be effective in certain circumstances. Typically, when the STOP signs are warranted due to comparable main street and side street volumes, compliance is good and speeds in the area are lower. When the STOP signs are not warranted, compliance goes down and the effectiveness of the device decreases as well. In addition, vehicles tend to speed up between the devices, possibly to make up for what they perceive to be "lost time" at the STOP signs. City research, published in 1994, documented speed data in the vicinity of six multi-way stop controlled intersections in the City of Boulder. In all cases, the speeds were well in excess of the posted speed limit. On the average, the average speed was 3 mph over the speed limit while the 85th percentile speed was 8 mph over the speed limit. These are speed profiles similar to or higher than most roadways currently in the NTMP. In 1997, city staff collected speed data at several locations where multi-way stop control was recently installed. In 1998, Staff performed tests on two trial locations where multi-way STOP sign control was temporarily installed. The data for these tests showed the use of STOP signs as a speed mitigation device had varied degrees of effectiveness. Table C6-1 outlines the results of the before and after speed data study. -C19- TABLE C6-1: Speed Data Comparison Before and After Stop Control Installation .a eaxix t,, i : .AYCTBQC speed ~95thTelCentllC speed Pro ect Street Before t1 er k Giiarigef efore g ` 1 ,f ,B % p Chan e N. Ninth Street (n/o Evergreen) 20 mph 24 mph +4 mph 23 mph 28 mph +5 mph 13th Street (n/o High ) 26 mph 24 mph -2 mph 33 mph 28 mph -5 mph Ninth Street (n/o University) 29 mph 28 mph -1 mph 33 mph 33 mph 0 mph Bear Mountain (n/o Wildwood) 28 mph 28 mph 0 mph 32 mph 32 mph 0 mph Pawnee Drive (n/o Thunderbird) 27 mph 24 mph -3 mph 31 mph 28 mph -3 mph (The methods used to collect traffic data are not 100 percent accurate. There are enough daily fluctuations on roadway speed/volume and limitations in the technology used to collect the data that the information should be used for comparative purposes only.) Staff also looked at the approach speeds of vehicles entering a multi-way stop controlled intersection to determine the speed reduction benefit near the intersection. The results showed surprisingly little reduction in speed within 50 feet of the STOP sign at these intersections. Table C6-2 outlines the results of this study. TABLE C6-2: Vehicle Speeds Within 50 Feet of Stop Signs Aaerdge approaeh 85th prcntrlappoaeh XvlamJstdetreet Intersectton :>p ed (CSO feet}peeOee} Vsilume distrtbuttoiV 13th & High 18 mph 20 mph 4 to 1 Wonderland & Poplar 18 mph 20 mph Unknown Manhattan & Cimmaron 19 mph 22 mph >20 to 1 Ninth & Dellwood 18 mph 21 mph 3 to 1 * volume factored to account for high numbers of pedestrians Public Innut City staff has received many requests to consider using STOP signs for speed control as part of the NTMP. In general, there has been very little concern expressed by the public concerning the general use of STOP signs in this fashion. The Transportation Division has generally not been using multi- way stop control unless it is warranted by high traffic volume, high accidents or sight distance restrictions. Given the limited role that STOP signs have played in traffic mitigation, there has been little reason to expect much comment from the public about the general use of STOP signs as traffic mitigation. In 1998, staff experimented with multi-way stop control at two locations where main street and side street volumes had a ratio of less than 5:1, and where potential traffic diversion would be unlikely to occur or would likely occur on a higher classification street. Considerable public comment was received as a result of both of these installations. There were many citizens who expressed support for -C20- the placement of the STOP signs. Many other citizens called to state that they did not supportlfavor the use of STOP signs at these locations. Most of the comments acknowledged that the STOP signs probably did little to reduce corridor speeds. However, there was also acknowledgment that the STOP signs did slow down speeds in the direct vicinity of the STOP sign. There was support for the STOP signs as a method to help facilitate pedestrian crossings and as a tool for discouraging traffic from traveling through these neighborhood streets. Several comments discussed how the STOP signs made it easier to traverse the intersection, especially for young children and elderly pedestrians. Concern was expressed about the potential safety issues associated with the poor compliance at the STOP signs. There were also some concern about noise and pollution impacts as a result of the STOP signs. There was considerable concern expressed about the inappropriateness of this type of traffic control at the locations selected. Several comments reflected the concern that the driver did not feel that it was appropriate to have to stop at this location. At least one comment reflected the fact that the driver was not speeding when they encountered the stop sign and was upset at being forced to stop when it was clear there was no traffic on the side street. There was a protest of the STOP signs on Bear Mountain Drive that lasted throughout the entire demonstration. Drivers of vehicles passing through the STOP signs, at various hours of the day and night, would honk their horns in protest. This prompted at least one citizen living near the intersection to contact staff on several occasions and request that the signs be removed immediately. SAFETY CONCERNS Compliance Compliance is another issue which has received considerable discussion and study by transportation engineers. In 1992, the City of Portland, Ore., studied the effects of STOP signs on several of their streets. The results showed that compliance was very poor at locations which were not warranted by national standards. As a result, Portland concluded that STOP signs should not be installed for the sole or primary purpose of reducing speed due to the potential negative impact on traffic safety. A recent study by the City of Pueblo, Colo., resulted in the same conclusions. City of Boulder Transportation Engineering staff evaluate requests for STOP signs based on national standards and professional judgement. Staff will post STOP signs at locations which meet the national standards in the Manual on Uniform Traffic Control Devices (MUTCD) and/or seem safe and reasonable. Since the creation of the NTMP, staff has been asked to experiment with multi-way stop control at several locations which did not meet MUTCD standards, primarily for the purpose of traffic mitigation. Transportation Engineering staff generally considers a STOP sign to be warranted when some clarification to right-of-way is necessary (a low volume street intersecting a high volume street) or when the physical characteristics of the intersection require that all vehicles stop to better provide for safe operation. Generally, compliance at a STOP sign is better when the amount of traffic on the main street and side streets are relatively high and when the volumes on the main street and side streets are similar. This is due to the fact that the probability of a main street vehicle encountering a side street vehicle at the intersection is higher. When these situations do not exist, lack of compliance can occur. -C21- In 1994, the City of Boulder published an article (January 1994 - Institute of Transportation Engineers (ITE) Journal) detailing findings on several aspects of multi-way STOP sign affects, at intersections in the City of Boulder. Between 0 percent and 16 percent of all traffic entering the 13 intersections studied ran the STOP signs on the main street. The percentage was higher for T-intersections than four-way intersections and also for side streets with very low volumes. The study also showed that an additional 60 percent to 89 percent of all traffic on the main street rolled through the intersection, traveling at 5 MPH or less. In 1997, Transportation staff performed similar compliance studies on several intersections with multi- way stop control. In 1998, staff performed similar compliance studies on the two intersections for which experimental multi-way stop control had been placed. Findings showed a higher rate of compliance than the 1994 study. However, there were still a high number of vehicles who ran the STOP signs (similar numbers to the 1994 study). The first three locations in Table C6-3 were made multi-way stop controlled intersections within the last year. The next four locations have been multi- way stop controlled for several years. The last two locations were the two intersections where staff experimented with multi-way stop control in 1998. TABLE C6-3: Stop Sign Compliance ' , d r ; „ ,5 ' e Matril de 9", U`j ° , Al~f'ealc PereeRt P1~ a` ~~erCCRtt~~ `~txeet,yolnme lIltetSeP.loR i ti s gtIIS r?..TQfdl.. -tif',$k(?RS- ~,dfQfal? + orShYbU#Ifi7R' Ninth St & Forest Ave 6 vehicles 5% 13 vehicles 9% 2.5 to 1 Ninth St & Dellwood Ave 1 vehicle <1% 6 vehicles 2% 3 to 1 13th St & High St 4 vehicles 1% 7 vehicles 2% 4 to I* Wonderland & Poplar 8 vehicles 8% 27 vehicles 16% 5 to I Manhattan & Cimmaron 8 vehicles 5% 12 vehicles 9% >20 to 1 Ninth St & Maxwell Ave. 4 vehicles <1% 0 vehicles 0% 4 to 1 Sixth St & Arapahoe Ave. 2 vehicles 1% 6 vehicles 4% Even Bear Mountain & Wildwood 16 vehicles 14% N/A N/A 4 to 1 Pawnee & Thunderbird 26 vehicles 10% N/A N/A 2 to 1 * volume factored to account for high numbers of pedestrians Most of the intersections chosen for this study did not have traffic volumes which would warrant multi- way stop control using national standards. The intersection of 13th Street and High Street received multi-way stop control to facilitate crossing of the children at Casey Middle School and Sacred Heart School. Both of the North Ninth Street intersections and the intersection of Manhattan and Cimmaron had multi-way stop~control installed as traffic mitigation. The intersections of Wonderland and Poplar and Ninth and Maxwell both have sight distance issues at the intersection which suggest the need for multi-way stop control. City records do not discuss the purpose for placing multi-way stop control at -C22- the intersection of Sixth and Arapahoe. Bear Mountain and Wildwood, and Pawnee and Thunderbird were temporary installations and have since been removed. Accident trends In 1992, the City of Portland, Ore., studied the effects of STOP signs on several of their intersections. They found that when multi-way stop control was installed at locations which did not meet MUTCD national warrants, accidents typically increased. As a result, the City of Portland concluded that STOP signs should not be used for the sole and primary purpose of speed control due to the potential negative impact on traffic safety. In some situations, the Transportation Division does recommend the use of STOP signs to mitigate safety problems. Generally, these are problems of sight distance or right-of-way control which are resulting in accidents. In 1996, the city installed multi-way stop control at the intersection of Ninth Street and University Avenue, to mitigate a right-angle collision accident problem. Two years later, the number of right-angle collisions had decreased but the number of rear-end collisions increased. The severity of accidents at the intersections dropped considerably. The use of multi-way stop control typically increases the total number of accidents at an intersection while decreasing the severity of those accidents. Staff uses STOP signs when they believe that severe accidents, which often result in major injuries, can be avoided or when such a changes would result in conditions to reduce speeds and reduce the chance of accidents with injuries. Compliance issues outlined in the section above bring into question the safety of using STOP signs, when compliance is likely to be low. The probability of a serious accident occurring increases when vehicles are ignoring the traffic control which defines right-of-way in the intersection. Vehicles which are relying on that traffic control to make good decisions about when to proceed are put at risk when other vehicles ignore the same traffic control. Staff has reviewed the accident history at several intersections which have multi-way stop control. The findings are inconclusive. Some locations have relatively high number of accidents with multi-way stop control while others have little or no accidents. These findings are consistent with national findings. The only common trend seemed to be that the higher the main street volume, the higher the number of accidents. The City of Boulder studies accident rates at intersections through the "Hazard Elimination Program." An accident rate which is higher than 2.0 accidents per million entering vehicles is considered to be unusually high and merits evaluation of possible accident reducing mitigation measures. The results of Table C64 show that the intersection of Ninth and Maxwell has a relatively high rate for a residential intersection. A rate of 1.8 accidents per million entering vehicles would probably put this intersection in the top 30 locations in the City. The intersections of Balsam/19th and Walnut/33rd also have high accident rates which would put them in the top 50 locations in the city. The intersections of Wonderland/Poplar and Sixth/Arapahoe have moderate accident rates; the intersection of Manhattan/Cimmaron has been without incident in the time period studied. -C23- TABLE C64: Accident Rates at Multi-way Stop Intersections -ant street Acazdent§rei'yar Acid)`'tior Ihfersech6n} yQar huerage} entertngvuoles otusle dtstnbutton= Ninth & Maxwell 5 1.8 4 to 1 Sixth & Arapahoe 2 1.3 Even 33rd & Walnut 4 1.5 3 to I Balsam & 19th 5 1.5 1.5 to 1 Wonderland & Poplar 1 1.3 4 to 1 Manhattan & Cimmart 0 0.0 >20 to 1 Bicyclists and Pedestrians Bicyclists and pedestrians using intersections with multi-way stop control should be at no more risk than any other user, provided the traffic control is receiving good compliance. However, staff's observations show that many bicyclists do not comply with the STOP signs themselves and therefore put themselves at risk from side street traffic. Pedestrians are at risk when vehicles do not comply with STOP signs, because pedestrians are less likely to be seen by an oncoming car. Emergency Response Delay is often experienced whenever an ambulance or fire engine must pass through an intersection which they do not have the inherent right-of-way. In 1998, city staff studied the effects of STOP signs on emergency response. Studies were done at two low volume intersections where trial STOP signs had been installed. These studies were done in the off-peak time periods. The results of these studies showed that the delay to emergency response in this situation was negligible (less than one second on average). The only time-significant delay occurred was when there were two or more other vehicles at the intersection, and this condition did not occur often. In 1999, staff studied the effects of STOP signs at a higher volume intersection. Studies were done at the intersection of 19th Street and Balsam Avenue during the p.m. peak hour. These studies showed that there was a considerable amount of emergency response delay resulting from the traffic control. Delay at the intersection varied between 5 and 12 seconds. The fire engine used in the experiment could not approach the intersection as fast as they would in an uncongested condition, and they had to slow to an average of 12 mph as they traversed the intersection itself. The impact that STOP signs have on emergency response is a varied effect. It seems to depend largely upon the traffic volume, the time of day and the geometrics of the intersection (whether there are parking aisles, neckdowns, etc...). However, it appears that on any roadway where there is higher traffic volumes (1,000 to 2,000 vehicles per day or higher), there is likely to be emergency response delay during some portions of the day, as a result of STOP signs. The Fire Department has indicated that multi-way stop control may be acceptable from an emergency response perspective on some lower volume roadways but should not be used on higher volume -C24- roadways as it will cause a delay in their emergency response time. The Fire Department's Master Plan states that any increase of delay upon their emergency response routes is "unacceptable." ENVIRONMENTAL CONCERNS The use of different mitigation treatments has several environmental/quality of life issues associated with them. Specifically, the effects of slowing, stopping, idling and accelerating increase automobile exhaust, noise and fuel consumption. VYthicle Emissions The act of stopping one's vehicle and accelerating back to speed has an impact on the amount of emissions put out by the vehicle. A study of 10 multi-way stop controlled intersections in Michigan showed that the average additional emissions per intersection each year was approximately 128,750 pounds of carbon monoxide, 7,920 pounds of hydrocarbons and 8,300 pounds of oxides of nitrogen. Using carbon monoxide emissions as an example, this represents an increase of approximately 0.2 percent per intersection per year over the annual emissions of Boulder Valley. Use of stop control as speed mitigation on all NTMP streets would likely result in as many as 50 additional multi-way stop control intersections. This would result in an increase of almost 7.5 percent of the annual emissions of Boulder Valley or an additional 8.8 tons per average winter weekday. A significant increase in emissions would be in direct conflict with the goals of the Transportation Master Plan which attempts to lower the tons of carbon monoxide emissions from 118 tons per day to between 35 to 60 tons per day. N ise The slowing and accelerating associated with any of the mitigation devices will result in localized noise impacts in the vicinity of the device. Since STOP signs require the greatest degree of slowing and acceleration to resume speed, the noise impacts are greatest with the use of this device (over the others discussed in this document). Also, since STOP signs increase the amount of time that vehicles are present at the intersection this will prolong the length that the additional noise is present. Fuel Consumption/Resource Impacts Fuel consumption and resource impacts are other environmental factors to be considered. A study performed in California in 1982 found that the deceleration and acceleration for each stop that an average passenger car makes would result in an increased consumption of 0.0173 gallons of fuel. On a roadway carrying 10,000 vehicles per day, this would translate to 173 gallons of fuel per day or 63,145 gallons per year. Using the example above of 50 intersections over the course of the NTMP, this would be an additional 3,157,250 gallons per year in the City of Boulder at a cost of over $4.0 million to be absorbed by the users of these intersections. PROGRAM RESTRICTIONS Diversion of Traffic to adjacent streets Staff does not have sufficient data to draw a conclusion about the diversion potential for STOP signs when used as a speed control device. Staff has not recommended employing STOP signs as a speed control device at any location in the city where there was not a logical higher classification street to which traffic could be diverted. A specific example is Ninth Street with Broadway as a parallel facility to handle diversion. -C25- OTHER CONSIDERATIONS Community Concems/City Policies The City of Boulder follows national standards for STOP sign installation, published by the Federal Highway Administration, which has been adopted by ordinance as official policy concerning the use of traffic control devices. This document discusses the "appropriate" uses for STOP signs and multi-way stop control. Specifically, it cites issues with right-of-way, high side street traffic volumes and documentable safety issues as reasons to employ STOP signs. These national standards state that "STOP signs should not be used for speed control." Concerning the placement of multi-way stop control, national standards state that it should ordinarily be used only where the volume of traffic on the intersecting roadways is approximately equal. -C26- SECTION C7: PHOTO RADAR ENFORCEMENT DESCRIPTION Photo-radar is an automated speed enforcement device using radar to determine the speed of vehicles interconnected with cameras to photograph vehicles traveling faster than the set violation threshold. In the City of Boulder photo-radar demonstration, the device is mounted in a van and deployed at different locations throughout the day. EFFECTIVENESS AS A MITIGATION TOOL 5peed Reduction The photo-radar unit is an excellent data collection device, logging the speed of all vehicles observed; speeding or not. An examination of data compiled by the photo-radar device during deployment was conducted. The speeding and violation percentages for deployments throughout the demonstration time line were analyzed. The analysis was performed on individual streets and streets grouped by functional characteristics. Functional groups included: Arterials; Collectors; r Locals; School Zones; and, Critical Emergency Response Routes (CERR) Results of this analysis indicate that on a majority of the streets and street groups, speeding and violation percentages are decreasing over time as continued deployment occurs. On a somewhat unusual note, the percent speeding (those going above the posted speed limit) seemed to be more impacted than the violation percentage (those going above the threshold which triggers the photo radar equipment). However, there were enough locations that did not show a reduction in speeding or violations to make the results of this analysis conclusive. Additionally, since the photo-radar unit is performing the data collection, its presence may have influenced driver behavior and the data as a result. Staff conducted separate independent speed studies on five neighborhood streets in June 1998 before implementation of the photo-radar demonstration. After six months of deployment, follow-up studies were performed in December 1998 without the photo-radar unit present to evaluate whether the residual affects of photo-radar had reduced vehicle speeds. (See Table C7-1 below) Results of these studies do not indicate that efforts to date have reduced vehicle speeds on these facilities. On each of the streets studied, there was no change to the average or 85th percentile speed. -C27- TABLE C7-1: Speed Data Comparison Before and After Photo Radar Implementation -ifi to Average , to*. a}tlr a centtle p s eed ...a - a` v t v, .v i ..per ;i s PIOeetJlreet at a f tu` sr+ v _1-. ai. q;$e€ore it `After '!.}rati_a~rAQc ~Ai=ter Ghange: Ninth Street (2100 block) 27 mph 28 mph +1 mph 31 mph 32 mph +1 mph Mapleton (2200 block) 24 mph 25 mph +1 mph 30 mph 30 mph 0 mph Balsam (1700 block) 29 mph 29 mph 0 mph 33 mph 33 mph 0 mph Brooklawn (900 block) 26 mph 28 mph +2 mph 31 mph 33 mph +2 mph Alpine (1400 block) 29 mph 30 mph +l mph 34 mph 34 mph 0 mph (The methods used to collect traffic data are not 100 percent accurate. There are enough daily fluctuations on roadway speed/volume and limitations in the technology used to collect the data that the information should be used for comparative purposes only.) In conclusion, after six months of citation deployment there is no statistically conclusive evidence that the photo-radar demonstration to date has reduced speeding in the City of Boulder. Limitations of our data collection and the short time frame studied may not provide an accurate picture of the device's effectiveness. In addition, staff does not have a clear sense yet of what level of photo radar enforcement would likely begin to change driver behavior. At approximately 1,000 to 1,500 citations issued per month, there is still quite a bit of the population that has not had any experience with photo radar enforcement. As time passes, and more and more citations are issued, people who speed frequently on neighborhood streets should be receiving their second (third, fourth, etc ) citation, and perhaps the cumulative effect of multiple violations will affect their driving behavior when a single ticket (or none) would not. It is possible that photo radar would yield a higher success with a change in either the number of units deployed in the city or longer term use of this tool (i.e., the use of this tool for a year rather than six months may show different results). Public Input/Community Support In February 1998, the city set up a phone message line for citizens to ask questions and give their thoughts on photo radar. Since February, thousands of messages have been left on the phone line with both support and nonsupport for the use of photo radar. More of the input received was opposed to photo radar rather than for support of photo radar. The number of daily calls received has varied since the message line was set up. Higher volumes of calls occurred when the message line was first set up, photo radar began and after articles were in the press. Citizens have also sent letters regarding their support or nonsupport for photo radar. To gauge public support of the use of automated enforcement techniques (photo-radar and photo red light) statistically significantly surveys were commissioned through CPPA. A survey was performed in June 1998 prior to beginning the demonstration to gauge initial sentiment. A follow-up survey was performed in November 1998 to reassess public support and determine if public opinion had shifted. A short summary is provided below. -C28- ;u P-1:5- Jg~ F.i, Do you favor the use of Photo-radar in Boulder? June 1998 November 1998 Change Strongly favor 20% 26% +6% 37% 48% +11% Somewhat favor 17% 22% +5% Neither favor nor oppose 9% 9% 5% 5% -4% 4% Somewhat oppose 15% 16% +1% 54% 47% -7% Strongly oppose 39% 31% -8% Total 100% 100% - Mean Rating (1= strongly oppose, 5= strongly favor) 2.1 2.4 +0.3 In the initial survey, the majority of respondents indicated that they were either "somewhat" or "strongly" opposed to the use of photo-radar. The follow-up results indicate a statistically significant shift in public support for the use of the technology, with respondents now equally split between favor and opposition. When asked why they favored or opposed the use of photo radar, approximately half said they favored it because it may decrease speeding/accidents. Those who opposed photo radar were most likely to cite fears of an invasion of privacy or "big brother;" more than 40 percent mentioned this reason in November while approximately 30 percent of those opposed gave this reason in June. Interestingly, while support for photo-radar increased from June to November, perceptions about the effectiveness of the device in reducing speeding remained unchanged. When asked how effective they believed photo radar would be in reducing speeding in Boulder, over half thought it would be very or somewhat effective in both June and November. SAFETY CONCERNS The use of photo radar is very similar to traditional enforcement. The fundamental difference is that it is automated. As such, staff does not believe there any significant safety issues associated with this tool. Bicyclists and Pedestrians Staff does not believe that this tool has any negative impact of bicycle use or pedestrian activities. Emergency Response Staff does not believe that this tool has any negative impact on emergency response. ENVIRONMENTAL CONCERNS Since the use of photo radar speed enforcement is a passive mitigation device, it does not have several of the environmental/quality of life issues associated with many of the physical mitigation devices or -C29- traffic control restrictions. Specifically, the photo radar unit does not cause artificial effects of slowing, stopping, idling and accelerating, which in turn increase automobile exhaust, noise and fuel consumption. Vehicle Emissions The photo radar unit does impact this area in one fashion. On particularly hot or cold days, the vehicle is left running throughout the deployment to protect the officer monitoring the unit from significant temperature impacts. This practice has a relatively small vehicle emissions impact. Noise Staff does not believe that the use of photo radar has any noise impacts. Fuel Consumption/Resource ImImpacts The photo radar unit impacts this area in one fashion. On particularly hot or cold days, the vehicle is left running throughout the deployment to protect the officer monitoring the unit from significant temperature impacts. This practice will have a relatively small fuel consumption impact. PROGRAM RESTRICTIONS Diversion of Traffic to adjacent streets Staff does not believe that the use of photo radar has resulted in any significant traffic diversion. OTHER CONSIDERATIONS Community Concerns/City Policies For further detail on citizen input and community concerns please refer to the Photo Radar Survey Results which can be found in Appendix F of the March 30, 1999 TAB/City Council Joint Study Session memorandum. -C30- SECTION C8: PHOTO RED LIGHT EXPERIMENT DESCRIPTION Photo red light is an automated enforcement tool used to monitor and ticket vehicles who run red lights at specific intersections. The device involves the use of a mounted camera at an intersection and a series of loop detectors in the roadway surface to monitor speed and the time of the vehicles approach, compared to the phasing of the traffic signal. If the loops detect that a vehicle is entering the intersection during the red phase for that approach movement, the camera takes a picture of the vehicle and driver, and a citation is issued to the driver. EFFECTIVENESS AS A MITIGATION TOOL Red Light Violation Reduction Violation percentage data was collected at six intersections, prior to the installation of the photo red light cameras. The cameras were then deployed at three intersections (four approaches) in the following locations: Valmont Road/47th Street (WB), 28th Street/Arapahoe Avenue (S/B and W/B) and Table Mesa Drive/Foothills Parkway (WB). Data collection was conducted in January 1999 at each of the intersections to see whether compliance had increased on: a) the approaches with photo red light; b) other approaches in the same intersection; and c) approaches on other intersections without photo red light enforcement. The results of these studies are shown in Table C8-1. The violation data is summarized for all movements in the intersection. The numbers represent violations occurring during one peak hour. TABLE C8-1: Ytolation,perceptageomp_rison Be#ore aril After Phttto Red Lrghf lmplementahon " k Percment Red 1L ghtV iolatio~r', Intersectton= Hefore [fret ge 28th Street & Arapahoe Road 79 45 34 (photo red fight) 47th Street & Valmont Road 4 8 +4 (photo red light) Table Mesa & Foothills/RTD 4 6 +2 (photo red light) 28th Street & Canyon Boulevard 39 51 +12 (no photo red light) Ninth Street & Canyon 5 14 +9 Boulevard (no photo red light) -C31- Baseline Road & Broadway 23 23 0 (no photo red light) The results of this study suggest that there may be some reduction of red light violations at intersections using photo red light. However, only one intersection with photo red light deployment actually showed a reduction in violations. The data does not support the theory that use of photo red light is decreasing red light violations at other intersections. None of the three intersections without photo red light deployment showed any increase in compliance. In addition, the photo red light cameras have been tracking violation information on the four deployment approaches since they were activated in October 1998. Problems during the program start up resulted in a lack of data for the month of October so there is only data available for November. The violation information being tracked is summarized in Table C8-2. TABLE C8-2: Photo Red light Violation Data - November 1998 fnferseetto"pproaeh' „ rol txots d rR .N { i ¢ d, pec;eCl Perfeeted eue a"feF Valmont & 47th Street - 291 26 8.9% 0.44 1.47 westbound approach per hour seconds Table Mesa & Foothills/RTD 188 41 21.8% 0.26 1.83 - westbound approach per hour seconds 28th Street & Arapahoe - 242 77 31.8% 0.40 2.09 westbound approach per hour seconds 27.5% l.26 1.74 28th Street & Arapahoe - 894 T-246, southbound approach per hour seconds "Violations detected" are the number of vehicles observed running a red light on each approach during the month. "Violations perfected" are the number of clear images with appropriate information that could be used to issue citations. "Violation rate" is the rate at which detected violations become perfected violations. "Violation frequency" is the number of red light violations detected per hour of deployment. The cameras were not functioning every hour of the month. The deployment time was influenced by the need to change film in the camera and by camera malfunctions throughout the month. "Violation time" is the average amount of time after the red light activated that violations occurred. Most traffic signals in the City of Boulder have between one and two seconds of all red time (time where the traffic signal is red in all directions) following each phase. The data suggests that, on average, approximately one vehicle per two hours is running a red light at these four intersections, and when they do so, they are typically entering the intersection between 1.5 seconds and 2.0 seconds after the light has changed. -C32- Public Input/Community Support The opinion surveys conducted in June and November of 1998 regarding automated enforcement also asked citizens about photo red light. Familiarity increased greatly since June, with the percentage of respondents who had heard of photo red light increasing from 34 percent to 66 percent. Both the initial and follow-up surveys indicate that the majority of respondents either "somewhat" or "strongly" favor the use of photo red light. The follow-up survey indicates that this support has grown. A tabular summary is provided below. . - ~ PntrlicSvpporf'forttief3se;ufPhotv~ie~LgLtti~'~'-~.,,. ' Do you favor the use of photo Red light in Boulder? June 1998 November 1998 Change Strongly favor 32% 39% +7% 57% 63% +6% Somewhat favor 25% 24% -1% Neither favor nor oppose 7% i% 5% 5% -2% Somewhat oppose 13% 10% -3% 36°.~ 32% -4% Strongly oppose 23% 22% -1% Total 100% 100% Mean Rating (1= strongly oppose, 5= strongly favor) 3.3 3.5 +0.2 The reasons most often given for supporting photo red light were increased safety and decreased accidents as well as increased compliance with traffic laws. Over one third of respondents opposed photo red light due to the fear of "big brother" or an invasion of privacy. Almost 60 percent of respondents thought photo red light would be "somewhat" or "very effective" in reducing accidents when asked in November. This represented a decline compared to June, when 70 percent of respondents rated photo red light as effective. SAFETY CONCERNS Accident reduction Several of the intersections chosen to receive the photo red light mitigation were selected due to a high number of accidents resulting from red light violation. The number of accidents resulting from red light violations were considered in all candidate intersections. Table C9-3 summarizes the average accidents per month, prior to the deployment of photo red light and following the deployment of photo red light at six of the candidate intersections. The intersections of 28th Street and Arapahoe Road, 471:4 Street and Valmont Road, and Table Mesa Drive and Foothills Parkway/RTD Driveway, each have photo red light enforcement deployed on one or more approaches (a total of six positions). The intersections of 28th Street and Canyon Boulevard, Sixth Street and Canyon Boulevard, and Baseline Road and Broadway, were all candidate locations which did not receive photo red light deployment. -C33- TABLE C8-3: Red I 1ght aeetdents CompansoQ before and After PhototedigttT"implementation' "k , { 3 X99&Redltht' '`cctdentrates a „"F `~TTg, 'l`''t iz ~';'..fi''~ uy#Ei F s a.; y~sr y P'~ ~L41.JG,4i"x'fa w~,n~... e!>re n, tiltE~*jl • ~i~*'.rt ft ~~a~.,.y a v 28th Street & Arapahoe Road 0.22 0.33 +0.11 (photo red light) 47th Street & Valmont Road 0.56 0.33 -0.23 (photo red light) Table Mesa & Foothills/RTD 0.33 0.00 -0.33 (photo red light) 28th Street & Canyon Boulevard 0.67 0.67 None (no photo red light) Ninth Street & Canyon Boulevard 0.00 0.00 None (no photo red light) Baseline Road & Broadway 0.00 0.33 +033 (no photo red light) There is a small trend towards a reduction in accidents resulting from red light violations at intersections with photo red light deployed at the intersection. There does not appear to be any reduction in these types of accidents at intersections without photo red light deployment. However, with only three months of deployment, there is insufficient data to draw any statistically significant conclusions on accident reduction benefit. Compliance The purpose of this device is to increase compliance when a vehicle encounters a red light. Staff feels that there can only be beneficial safety results from deployment of photo red light enforcement. Bicyclists and Pedestrians Staff does not believe that this tool has any negative impact of bicycle use or pedestrian activities. Emergency Response Staff does not believe that this tool has any negative impact on emergency response. ENVIRONMENTAL CONCERNS Staff does not believe that this tool has any negative impact on air pollution, fuel consumption or noise impacts. PROGRAM RESTRICTIONS Diversion of Traffic to adjacent streets Staff does not believe that the use of this tool has resulted in any significant traffic diversion. -C34- SECTION C9: SPEED SENSITIVE TRAFFIC SIGNALS DESCRIPTION R&st in All-Red Speed Sensitive Signal Operation The speed sensitive traffic signal demonstration involved taking an existing traffic signal (the intersection of Pine Street and 20th Street) and introducing an influence on the timing of the traffic signal related to the approach speeds of the vehicles on the roadway. The traffic signal would have red light indication in all directions, unless a vehicle was approaching the intersection. If that vehicle were driving the speed limit (monitored by a series of inductive loops in the asphalt), then the signal indication would change to green before the vehicle entered the intersection. If the vehicle was speeding, then the signal indication would not change to green until well after the vehicle reached the intersection. Signs indicating that speeding would influence the signal control were posted on approaches to the intersection. The "rest in all-red" speed sensitive traffic signal demonstration involved modifying an existing traffic signal at the intersection of Pine Street and 20th Street to introduce an influence on the operation of the traffic signal related to the approach speeds of the vehicles on the roadway. This location was chosen in part because "rest in all-red" signal operation does not favor one street over the other, making it appropriate for intersections of streets with similar traffic volumes, such as Pine Street and 20th Street. The traffic signal was equipped with advance detection loops in addition to the standard detection loops at the stop bars and was programmed to display a red light in all directions when no vehicles are being detected. When a vehicle approached the intersection, the advance loops measured the vehicles speed. If the vehicle is traveling at or below the 25 mph speed limit, the controller is notified of the arriving vehicle. Unless another vehicle is already being served on the cross street, the signal turns green before the vehicle arrives at the intersection, and it proceeds without delay. If the vehicle is traveling above the speed limit, it is ignored until it stops at the stop bar, where it is detected in the traditional manner. Advance loops were also installed in the bike lanes on all four approaches to allow approaching bicyclists to trigger a green light, and "SPEED SENSITIVE SIGNAL" signs were posted to indicate that speeding would influence the signal operation. EFFECTIVENESS AS A MITIGATION TOOL Speed Reduction Speed data collection was performed on Pine Street, east and west of the intersection, prior to the change in signal operation. A follow-up study approximately four months after the signal change was also performed. The results of these studies are shown in Table C9-1. -C35- TABLE C9-1: Speed Data Comparison Before and After Photo Radar Implementation z+ bS1Gejlf.~?,,'°, ai~s~'kEStC'rrienIei'. speed, v & aI i~.^F.° 'F ,s'-4F 7 '~~eyayY ~.i `max' rxF F7 c ,rte- J c fia { rrfi a pjL ha (BefpB e hang ?:~efOYe er t s Change Plcr~eottree Pine Street (1900 block) 25 mph 25 mph 0 mph 29 mph 29 mph 0 mph Pine Street (2000 block) 27 mph 26 mph -1 mph 31 mph 31 mph 0 mph (The methods used to collect traffic data are not 100 percent accurate. There are enough daily fluctuations on roadway speed/volume and limitations in the technology used to collect the data that the information should be used for comparative purposes only.) It should be noted that both of these sections of Pine Street also received photo radar enforcement during the speed sensitive signal experiment. The data in Table C9-1 suggests that the speed sensitive signal experiment did not change vehicle speeds. Public lnl2 The input received on this speed mitigation demonstration was mostly positive. Reasons cited for support included no emergency vehicle delay, doesn't endanger cyclists and it punishes or rewards drivers immediately. Concerns included expense and possible air quality impacts. SAFETY CONCERNS Compliance Some concern was expressed that the use of a traffic control device in this fashion would result in less compliance with the red light indication and ultimately result in a less safe operation of the traffic signal. Red light compliance data was collected on Pine Street, during the AM and PM peak hours, prior to the change in signal operation. A follow-up study was performed during the experiment. The results of this study showed that the overall number of red light violations did not increase during the experiment. Staff does not believe that the use of this tool results in any significant safety impacts. . Bicyclists and Pedestrians Staff does not believe that this tool has any negative impact of bicycle use or pedestrian activities. Emergency Response Staff does not believe that this tool has any negative impact on emergency response. ENVIRONMENTAL CONCERNS See comments for speed humps, Section C 1. PROGRAM RESTRICTIONS Diversion of Traffic to adjacent streets Staff does not believe that the use of this tool has resulted in any significant traffic diversion. -C36- REST IN GREEN SPEED SENSITIVE SIGNAL OPERATION An alternative to the "rest in all-red" type of speed sensitive signal is "rest in main street green." This variation of speed sensitive signal operation may be more appropriate at intersections of streets with unequal traffic volumes where there is a higher volume "main street" and a lower volume "side street." As with typical traffic signal operation, a "rest in main street green" speed sensitive signal normally displays a green light for the main street unless traffic is detected on the side street. However, a "rest in main street green" signal has detection loops on the main street to measure the speed of approaching vehicles and turns the main street signal red when a vehicle traveling over the speed limit is detected, requiring it to stop. The existing traffic signal at Baseline Road and 17th Street was identified by staff as an appropriate location for a demonstration of "rest in main street green" speed sensitive signal operation. However, limitations in the existing traffic signal controller software used in Boulder have prevented the demonstration from being implemented. The controller software is scheduled to be replaced in 1999 as part of the signal system upgrade, and the replacement software is currently under development. Staff is seeking to include the capability for "rest in main street green" operation in the new software and will proceed with the demonstration when it is completed and installed later this year. -C37-