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Human Factors Guidelines for Road Systems: Second Edition (2012)

Chapter: Chapter 15 - Special Considerations for Urban Environments

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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Suggested Citation:"Chapter 15 - Special Considerations for Urban Environments." National Academies of Sciences, Engineering, and Medicine. 2012. Human Factors Guidelines for Road Systems: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/22706.
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Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Methods to Increase Driver Yielding at Uncontrolled Crosswalks . . . . . . . . . . . . . . . . . . . . .15-2 Methods to Increase Compliance at Uncontrolled Crosswalks . . . . . . . . . . . . . . . . . . . . . . . .15-4 Methods to Reduce Driver Speeds in School Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-6 Signage and Markings for High Occupancy Vehicle (HOV) Lanes . . . . . . . . . . . . . . . . . . . . .15-8 Sight Distance Considerations for Urban Bus Stop Locations . . . . . . . . . . . . . . . . . . . . . . . .15-10 15-1 C H A P T E R 15 Special Considerations for Urban Environments

M ET HO DS TO I NC RE AS E D RI VE R Y IE LD IN G AT U NC ON TR OL LE D C RO SS WA LK S In tr od uc ti on This guideline provides an overview of some methods that can be used to increase driver yielding at uncontrolled crosswalk s . Uncontrolled crosswalks are crosswalks that cross the roadway at a location where no stop or signal control exists. They ma y be mi dblock or at an intersection with tw o-way traffic control. Uncontrolled crosswalks include those which have pedestrian signals such as a half signal or HAW K signal. These crosswalks are often desirable to improve pedestrian access to points that lie between, and perhaps far from, an associated controlled intersection crossing. However, at uncontrolled locations on two-lane roads, marked crossw alks provide no crash rate reduction when compared to unmarked crosswalks ( 1 ). Although pedestrians in ma rked crosswalks are mo re likely to have drivers immediately yield to them , this higher rate of yielding ma y lead to multiple-threat co llisions on roadways with mu ltiple lanes in each direction ( 2 ). Therefore, it is important to ensure that pedest rians using marked crosswalks and drivers approaching mark ed crosswalks have adequate sight lines and actively look for one another. De si gn Gu id e lin es Im prove sight lines between the driver and the pedestrian(s) by: • Installing yield lines • Installing bulbouts • Prohibiting parking between the yield line and the crosswalk Convey the need for drivers to look for crossing pedestrians by: • Installing Roving Eye displays • Installing “Yield Here to Pedestrians” signs (along with yield lines) The width of the bulbout (in feet) that ma y be seen fro m the nearest travel lane at the stopping sight distance from the yield line is show in the table below. Posted Speed Deceleration Level (ft/s2) Parking Distance from Crosswalk (in feet) 0 10 20 30 40 50 30 mi /h 11.2 0.2 0.7 1.3 1.8 2.4 3.0 13.8 0.2 0.8 1.4 2.1 2.7 3.3 17.7 0.2 0.9 1.6 2.3 3.0 3.7 40 mi /h 11.2 0.1 0.5 0.8 1.2 1.5 1.9 13.8 0.1 0.5 0.9 1.3 1.7 2.1 17.7 0.1 0.6 1.1 1.5 2.0 2.4 As su mp ti on s: Driver eye is at the mi dpoint of the left half of the vehicle; the roadway is straight; the pedestrian stands in the mi ddle of the bulbout (when looked at along the axis of the roadway); perception-response time is 1.6 s; vehicles are parked 1 ft fro m the curb; deceleration levels are fro m AASHTO ( 3 ) “com fortable” level (3.4 m/ s 2 ); vehicles in the parking lane are parked up to the yield line but not between the yield line and the crosswalk. Ba sed Primarily on Ex pert Jud g ment Based Equally on Expert Judgment and Empirical Dat a Based Primarily on Em pirical Da ta HFG URBAN ENVIRONMENTS Version 2.0 15-2

Di scu ssi on Improve sight lines: The desired driver action at an uncontrolled crosswalk varies based upon the presence or absence of a pedestrian. In a field study of midblock crosswalks, the addition of yield lines and “Yield to Pedestrians” signs increased the likelihood that drivers look to the right for crossing pedestrians ( 4 ). For drivers who yielded, the treat me nts also led to an increase in distance between the vehicle and the crossi ng pedestrian. However, the proportion of drivers who yielded only increased with the addition of the treat me nts when the sight distance was adequate to see waiting pedestrians. Without im provements in sight distance, drivers with advance yield markings are unable to see pedestrians in their peripheral vision due to cars parked in the parking lane. Garay-Vega, Fisher, and Knodler ( 4 ) suggest that this situation is comparable to that which causes multiple-threat collisions. Th ese collisions occur when the pedestrian enters traffic in front of a stopped vehicle and collides with another vehicle traveling in the same direction in a lane past the stopped vehicle. Convey need to look for pedestrians: The pushbutton-activated roving eye treatments (animated eye graphics included in signals) were tested at two sites with me dians, crosswalks, and yield bars ( 5 ). Although only 30% to 40% of pedestrians activated the roving eyes, activation significantly increased at one site with enforcement. The roving eyes generally im proved yielding behavior in both directions, though low levels of pedestrian activation impaired the results. De si gn Is su es The issue of whether to ma rk the crosswalk is controversial. Zegeer ( 1 ) found that mu ltiple-threat collisions are mu ch more likely to occur at ma rked crosswalks. However, in a study of marked and un ma rked matched pairs of crosswalks, Ragland and Mitm an ( 2 ) found that pedestrians in marked crosswalks were more likely to have drivers immediately yield to them . Although when asked, significantly fewer drivers than pedestrians knew that pedestrians legally have the right of way at marked midblock crosswalks (44% to 74%, respectively). It is hypothesized that pedestrians exhibit an ordinary level of caution in marked crosswalks because they know drivers must yield to them and/or their experience has taught them that mo re drivers are likely to yield. However, in un ma rked m idblock crosswalks, 72% of drivers and 76% of pedestrians knew that pedestrians did not have the right of way. It would be reasonable to assume that pedestrians would exhibit greater caution in crossing under these conditions either because they know that they do not have the right-of-way and/or because their experience has been that drivers will not yield. Indeed, in the unmarked crosswalks, pedestrians waited for larger gaps (5/6 sites) and m oved at a faster pace (4/6 sites) than in the ma rked crosswalks. Even with the installation of bulbouts and the recommended parking restrictions, pedestrians may not be able to be seen by drivers depending on the part of the bulbout on which they stand. Fitzpatrick et al. ( 6 ) list the body depth for standing area calculations as approximately 1.6 ft. The table on the previous page shows the width of the bulbout (perpendicular to the traveled way) that can be seen by drivers passing in the nearest lane. Though the MUTCD ( 7 ) guidance recommends that yield or stop lin es be installed 20 to 50 ft in advance of th e nearest crosswalk line, the inclusion of the 0-ft and 10-ft parking distances simulate multiple-threat crash scenarios where vehicles may stop right next to the crossing pedestrian. The widths would decrease if vehicles wider than 7 ft parked near the curb. Pedestrians may not feel comfortable standing right on the edge of the bulbout, especially those using wheelchairs or other assistive devices. Cr os s Re fe re nc es Human Factors Considerations in Traffic Control Device Selection at Rail-Highway Grade Crossings, 14-12 Methods to Increase Compliance at Uncontrolled Crosswalks, 15-4 Methods to Reduce Driver Speeds in School Zones, 15-6 Ke y Re fe re nc es 1. Zegeer, C.V., Stewart, J. R., Huang, H.H., Lagerwey, P.A., Feaganes, J., and Cam pbell, B.J. (2005). Safety Effects of Marked versus Unmarked Crosswalks at Uncontrolled Locations: Final Report and Recommended Guidelines. (FHWA-HR T-04-100). McLean, VA: FHWA. 2. Ragland, D.R. & Mitm an, M.F. (2008). Driver/Pedestrian Understanding and Behavior at Marked and Unmarked Crosswalks (UCB-ITS- TSC-2008-10). Berkeley: University of California Traffic Safety Center . 3. AASHTO (2011). A Policy on Geometric Design of Highways and Streets . Washington, DC. 4. Garay-Vega, L., Fisher, D.L., & Knodler, M.A. (2008). Drivers' perfo rm ance in response to sight-lim ited crash scenarios at m idblock crosswalks: Evaluation of advance yield ma rkings and symbolic signage. Proceedings of the Human Factors and Ergonomics Society 52nd Annual Meeting, 1835-1839. 5. Nee, J., & Hallenbeck, M.E. (2003). A Motorist and Pedestrian Behavioral Analysis Relating to Pedestrian Safety Improvements. (WA-RD 560.1). Olym pia: Washington State Departm ent of Transportation. 6. Fitzpatrick, K., Turner, S.M., Brewer, M., Carlson, P.J., Ullm an, B., Trout, N.D., & et al. (2006). TCRP Report 112/NCHRP Report 562: Improving Pedestrian Safety at Unsignalized Crossings. Washington, DC: Transportation Research Board. 7. FHWA (2009). Manual on Uniform Traffic Control Devices for Streets and Highway s. Washington, DC. 15-3 HFG URBAN ENVIRONMENTS Version 2.0

METHODS TO INCREASE COMPLIANCE AT UNCONTROLLED CROSSWALKS Introduction Methods to increase compliance at uncontrolled crosswalks refers to treatments that improve pedestrian safety. These improvements are realized through safer pedestrian behavior and increased compliance with crossing treatments. These treatments should increase safety without decreasing crosswalk use and without excessive pedestrian delay. It is also important that they are designed so that pedestrians will find the treatments to be beneficial and thus activate them as necessary. The following guideline describe s the information needs of drivers at uncontrolled crosswalks. These needs should be provided for by using the appropriate engineering countermeasures, roadway design treatments, and traffic control devices. Note that not a ll of the potential treatments suggested below are warranted on all road types based on vehicular and pedestrian traffic volumes. Design Guidelines • Install a median refuge island to influence location choices for pedestrian crossing s . • Provide a maximum pedestrian delay of 30 - 60 s when using signalized treatments. • Clearly indicate the required driver actions. C OMPLIANCE WITH V ARIOUS T REATME NTS AT U NCONTROLLED C ROSSWALKS Treatment Type Average Driver Yielding Compliance Pedestrian Crosswalk Use Pedestrian Activation Average Initial Pedestrian Delay (s)* HAWK Signal Beacon 99% 90% 70% 9.63 Half Signal 98% 80% 67% 17.06 Midblock Signal 95% 95% 67% 26.35 In - Street Signs 90% 93% N/A 2.15 Pedestrian Crossing Flags 74% 88% 17% 2.72 Overhead Flashing Beacons ( Automated Pedestrian Detection ) 67% 87% 58% *** 5.62 Overhead Flashing Beacons (Pushbutton Activation ) 49% 82% 28% 5.44 Median Refuge 29% 82% N/A 9.22 High - Visibility Signs/Markings 20 - 91%** 89% N/A 2.39 * Combined delay at start of crosswalk and in median. **Average compliance lower on 35 mi/h roadways than 25 mi/h roadways. ***Reasons the system did not activate include: detector malfunctions, missed detections, and crosswalk incompliance. Source: Fitzpatrick et al. ( 1 ) E XAMPLE T REATMENTS HAWK Signal Beacon Median Refuge Island In - Street Signs Source: Fitzpatrick et al. ( 1 ) Based Primarily on Expert Judgment Based Equally on Expert Judgment and Empirical Data Based Primarily on Empirical Data HFG URBAN ENVIRONMENTS Version 2.0 15-4

Di scu ssi on Median refuge islands: Wh en median refuges were installed, significant numbers of pedestrians used them for crossing (36-46%, 2 ). These percentages increased even more with the add ition of crosswalks and yield bars. Providing a pedestrian refuge decreases nearside gap rejection ( 3 ) and allows pedestrians to cross the roadway in two stages. Another type of me dian is the extended median, sometimes used at split midblock signals. With this type of median, delay to vehicles is reduced by requiring the pedestrian to activate the signal for one half of the street, cross to the median, walk 100 ft down the center me dian, and push another button to activate the signal on the other half of the street. In an on-street survey, Ullm an, Fitzpatrick, and Trout ( 4 ) found that pedestrian opinions of extended medians varied based upon the pedestrian’s abilities. At the location with a greater nu mb er of disabled and older pedestrians, the extended median was viewed more favorably than at the location without this pedestrian population, where it was seen as an unnecessary delay. Pedestrian signal response time: Van Houten, Ellis, and Ki m ( 5 ) studied two signalized midblock crosswalks in Miami, Florida, by varying the minimum green time of the oncoming vehicles to 30, 60, and 120 s. It was found that the percentage of pedestrians who violated the “Don’t Wa lk” signal was greater at both intersections when the 60- or 120-s mini mu m green ti me s were used. Proportionately mo re pedestrians violated the signal at 120 s than at 60 s. As the length of the minimum green time increased, more pedestrians were trapped in the crosswalk (23% at 120 s). When the minimum green time was short, mo st pedestrians waited for the “Walk” sign, decreasing their likelihood of becoming trapped. However, when the mi nimum green ti me was 30 s, vehicle delay was longer than the pedestrian delay. Additionally, increasing the pedestrian clearance time to allow slower pedestrians to cross may cause longer mi nimum green ti me s and thus increase pedestrian violations. FHW A ( 6 ) recommends an al mo st immediate response to pedestrian activation to encourage co mpliance. Using on-street pedestrian surveys, Ullm an et al. ( 4 ) found that about 75% of participants at six sites stated that they should have to wait less than a minute before being able to cr oss the street. However, this value ma y differ when exam ined as actual pedestrian actions. A short response tim e to pedes tr ian button pushing is im portant because if pedestrians push the button and do not get a fast response, they may cross at the first am ple gap (depending on traffic levels). Then, when the signal turns red for drivers, no pedestrians will be crossing, possibly encouraging driver disrespect for the signal in th e future ( 6 ). Provide a clear indication of the required driver action: The red signals and beacons form a class of warning devices that clearly signifies the required driver action. Fitzpatrick et al. ( 1 ) found that red signal treatments had compliance rates above 94%. The treatments that showed a red indication had a statistically higher co mp liance rate than those that did not. It was hypothesized that this is because they send a clear me ssage to “Stop.” Nearly all of these devices were tested on busy, high-speed arterials ( 1 ). De si gn Is su es Fluorescent yellow-green is presented in the MUTCD ( 7 ) as a color option for some pedestrian crossing signs; however, Clark, Hummer, and Dutt ( 8 ) found that the use of the color only increased slowing or stopping behavior at three of seven sites studied and did not change conflict rates significantly. A potential issue is pedestrians congregating on the sidewalk near mi dblock crosswalks. If uncontrolled crosswalks are installed near locations where groups of pedestrians stand to socialize or wait for the bus, it may be mo re difficult for passing drivers to notice a pedestrian who is waiting to cross against the background of all of the stationary pedestrians. Cr os s Re fe re nc es Countermeasures for Im proving Accessibility for Vision-I mp aired Pedestrians at Roundabouts, 10-10 Methods to Increase Driver Yielding at Uncontrolled Crosswalks, 15-2 Ke y Re fe re nc es 1. Fitzpatric k, K., Turner, S.M., Brewer, M., Carlson, P.J., Ullm an, B., Trout, N.D., & et al. (2006). TCRP Report 112/N CHRP Report 562: Improving Pedestrian Safety at Unsignalized Crossings. Washington, DC: Transportation Resear ch Board. 2. Nee, J., & Hallenbeck, M.E. (2003). A Motorist and Pedestrian Behavioral Analysis Relating to Pedestrian Safety Improvements. (WA-RD 560.1). Olympia: Washington State Depart me nt of Transportation. 3. Hunt, J., & Abdulja bbar, J. (1993). Crossing the road: A method of assessing pedestrian crossing difficulty. Traffic Engineering and Control, 34 (11), 526-532. 4. Ullman, B., Fitzpatrick, K., & Trout, N. (2004). On-street pedestrian surveys of pedestrian crossing treatments. Proceed ings of the ITE 2004 Annual Meeting and Exhibit . 5. Van Houten, R., El lis, R. D., & Ki m, J.-L. (2007). Effects of various minimum green times on percentage of pedestrians waiti ng for mi dblock “walk” signal. Transportation Research Record, 200 2 , 78-83. 6. FHWA (2006). Federal Highway Ad mi nistration University Course on Bicycle and Pedestrian Tr an sportation. Lesson 12: Midblock Crossings. Retrieved July 2011 from http://www.fhwa.dot.gov/publications/research/safety/pedbike/05085/pdf/lesson12lo.pdf. 7. FHWA (2009). Manual on Uniform Traffic Control Devices for Streets and Highway s . Washington, DC. 8. Clark, K. L., Hu mmer, J.E., & Dutt, N. (1996). Field evaluation of fluorescent strong yellow-green pedestrian warning signs. Transportation Research Record, 1538 , 39-46. 15-5 HFG URBAN ENVIRONMENTS Version 2.0

M ETHODS TO R EDUCE D RIVER S PEEDS IN S CHOOL Z ONES Introduction Methods to reduce driver speeds in school zones refers to traffic control devices and pavement markings that are used to encourage drivers to drive at lower speeds in school zones. Maintaining safe speeds is particularly important in school zones for multiple reasons: (1) children have a greater tende ncy to behave unexpectedly near roadways than adults ( 1 ), (2) the probability of a pedestrian fatality rises from about 10% to approximately 60% when vehicle-impact speeds increase from 23 to 28 mi/h ( 2 ), (3) providing a reduced speed zone gives drivers a reduced stopping distance when forced to attempt to stop in reaction to a child hazard, and (4) reduced driver speeds also provide safer gaps for children to cross the street ( 3 ). Application of the guidelines below should encourage sl ower driving and facilitate the safety of children in school zones. Design Guidelines School Zone Speed Characteristic Guideline Active Times ( 4 ) The school zone speeds indicated on the signs should be in effect only from: • 30 min before to 5 min after classes begin • The beginning to the end of lunch periods for open campuses • 5 min before to 30 min after classes end School Speed Limit Value ( 4 ) 85th Percentile Speed Suggested School Zone Speed Limit < 55 mi/h Not more than 15 mi/h below the 85th percentile speed or posted speed. Not to exceed a 35-mi/h school speed limit. 55 mi/h 20 mi/h below the 85th pe rcentile speed or posted speed. > 55 mi/h Use a buffer zone to transition to a 35-mi/h school speed limit. School Speed Limit Zone Length ( 4 ) • As short as 400 ft in urban areas with speeds ≤ 30 mi/h • 1000 ft in rural areas with posted speeds ≥ 55 mi/h School Buffer Zone ( 4 ) • Use when the difference between the regulat ory speed limit and the school speed limit is > 20 mi/h • Typically 500 ft in length • Buffer zone beacons can activate up to 5 min be fore school speed zone beacons (see figure on next page) School Entrance Warning Assembly ( 4 ) Do not use if: • A school speed limit zone is present Conditions for use could include: • Crash records show a need to advise drivers to reduce speeds • The majority of students are transported by bus or private vehicle • No provisions are made for students to walk to/from school • No left- or right-turn lanes are present on the highway at the school driveway, or queue spillover from turning vehicles is present, or me thods to address the spillover have not worked • The entrance is not controlled by traffic signals Sign/Device Choice ( 2 ) The signs indicating a school speed limit were eff ective when the lights were flashing, and caused the greatest speed reductions on 35-mi/h roadways. Speed Monitoring Displays ( 5 ) Speed monitoring displays were effective in re ducing vehicle speeds by 17.5% and 12.4% in the short- and long-term studies, respectively. Based Primarily on Expert Jud g ment Based Equally on Expert Judgment and Empirical Data Based Primarily on Empirical Data HFG URBAN ENVIRONMENTS Version 2.0 15-6

Di scu ssi on A key data source in this area and a key contributor to this guideline is Fitzpatrick, Brewer, Obeng-Boampong, Park, and Trout ( 4 ), in which a variety of methods were used to doc um ent existing knowledge and develop guidelines for school zone traffic control devices. Key me thods included a litera ture review, a survey of practitioners on signing and ma rking practices, a telephone survey of law enforcement officers, and a review of state and local guidelines for school zones. The figure below (adapted fro m 4 ) shows key results for school zone speed li mi ts. S CH OOL Z ON E S P EED L IMIT S Source: Fitzpatrick et al. ( 4 ) De si gn Is su es The effectiveness of school zone flashers on vehicular speed is unclear. Aggarwal and Mortensen ( 6 ) found a significant reduction in vehicle speeds with the use of advance school flashers. W hen Hawkins ( 7 ) tested the beacons on school zones on highways, however, the speed differences were li mited. One benefit mentioned by Hawkins (7) and observed by Hawkins ( 8 ) on speed limit signs is that flashers also serve the purpose of indicating when the school zone is active. Cr os s Re fe re nc es Speed Perception, Speed Choice, and Speed Control Guidelines, 17-1 Methods to Increase Driver Yielding at Uncontrolled Crosswalks, 15-2 Task Analysis of Rail-Highway Grade Crossings, 14-2 Ke y Re fe re nc es 1. Tay, R., & Li, S.J. (2008). Drivers’ perceptions and reactions to chain link fence. Transportation Research Board 87th Annual Meeting Compendium of Papers [CD ROM]. 2. Saibel, C., Salzberg, P., Doane, R., & Moffat, J. (1999). Vehicle speeds in school zones. ITE Journal, 69 (11), 38-42. 3. Saito, M., & Ash, K.G. (2005). Evaluation of Four Recent Traffic Safety Initiatives, Volume IV: Increasing Speed Limit Compliance in Reduced Speed School Zones. (Report UT-05.13). Salt Lake City: Utah Department of Transportation. 4. Fitzpatrick, K., Brewer, M.A., Obeng-Boam pong, K., Park, E.S., & Trout, N.D. (2009). Speeds in School Zones. (FHWA/TX-09/0-5470-1). College Station: Texas Transportation Institute. 5. Lee, C., Lee, S., Choi, B., & Oh, Y. (2006). Effectiveness of speed-m onitoring displays in speed reduction in school zones. Transportation Research Record, 1973 , 27-35. 6. Aggarwal, G.C., & Mortensen, S.L. (1993) . Do advance school flashers reduce speed ? ITE Journal, 63 (10), 24-30. 7. Hawkins, N.R. (1993). Modified signs, flashing beacons and school zone speeds. ITE Journal, 63 (6), 41-44. 8. Hawkins, H.G. (2007). Rear-facing school speed lim it beacons. ITE Journal, 77 (6), 18-23. 15-7 HFG URBAN ENVIRONMENTS Version 2.0

S IG NA GE AN D M AR KI NG S FO R H IG H O CCU PA NC Y V EH IC LE (H OV ) L AN ES In tr od uc ti on Managed and reserved lanes are lanes usually designed for roadway networks in highly congested metropolitan regions where High Occupancy Vehicles (HOV) are prom oted and main tained as part of a network freeway management program. “An exclusive HOV roadway is an entire highway facility reserved at all times solely for the use of buses or buses and other HOVs. This facility offers buses and HOVs a high level of service and decreases travel tim e for the users” ( 1 ) . Other HOV roadways are only exclusive during certain hours of the day. These lanes have various restrictions that do not apply to the norm al travel lanes. The signage and markings used to discri mi nate these lanes is essential for motorists to understand usage rules and the special nature of the lane. De si gn Gu id e lin es The following recomm endations should be considered when designing signage and ma rkings of HOV lanes. These recommendations should facilitate motorists’ understanding of usage rules and the special nature of these lanes. Design Element Design Guideline Signage • Use “HOV” text rather than HOV diam ond sym bol on signage ( 2 ) • Avoid using “HOV/TOLL Lane” banner ( 2 ) • Provide distance destination signs and interchange sequence signs in advance of all access points to and from ma naged lanes ( 2 ). • Preferential lane sign information sequence (M1): − Top line: lanes to which the preferential treatment applies (e.g., left lane) − Middle line: applicable vehicles (e.g., buses only) − Bottom line: applicable time and date (e.g., 7-9 am, Monday-Friday) • If sign is m ounted overhead, then ti me and date should be separated by a downward arrow • Use overhead-m ounted signs instead of shoulder-m ounted signs where possible ( 3 ) • Lane control signals (e.g., red X indication in closed lanes) are well understood and can be used ( 3 ). Markings • Avoid using the word “only” and the arrow sym bol ( 4 ) • Avoid using “No Exit” text on the roadway ( 4 ) • Contra-flow lanes: use yellow pavem ent markings to delineate between HOV and mixed-use lanes • Concurrent flow lanes: use white pavem ent markings to delineate, and solid lines to show areas where crossing is not allowed • Use solid HOV diam ond sym bols instead of outlines ( 3 ). Based Primarily on Expert Jud g men t Based Equally on Expert Judgment and Empirical Dat a Based Primarily on Empirical Da ta HFG URBAN ENVIRONMENTS Version 2.0 15-8

Discussion There are relatively few data sources that can be used to develop comprehensive guidelines on this topic. The studies by Chrysler (2, 4) provide the best-available data for the design of signs and markings, and the guidelines above rely quite heavily on these laboratory studies. In Chrysler (2), computer-based surveys were used to obtain data from 142 drivers in Texas. The surveys used video animations and still images of signs to assess driver comprehension of managed lane signs that presented information related to pricing, occupancy, and destinations. Although there were some methodological concerns about the legibility of the animations used, the study yielded useful information on the characteristics of managed lane signs that seem to be associated with the highest levels of comprehension. For example, Chrysler found that letters “HOV” were better understood vs. the diamond symbol. Drivers also showed poor comprehension with the “HOV/TOLL Lane” banner. Half of the respondents incorrectly understood the banner to mean that only carpools are allowed, and they must pay a toll. This misunderstanding would prevent toll-paying single occupant vehicle drivers from entering the lane when they were actually allowed. Also, the HOV diamond symbol in the corner of the sign is still misunderstood by 15-25% of drivers to mean “Official Vehicles Only.” The text “HOV” was well understood by over 90% of participants (2). Advanced destination signing is an important determinant of whether drivers will use a managed lane. Previous studies show that one of the main reasons drivers do not enter HOV lanes is uncertainty about destinations served. Chrysler found that distance destination signs and interchange sequence signs should be provided in advance of all access points to and from managed lanes. Interchange sequence signs for managed lane exits may need to be made more distinct to avoid confusion with signing for the general purpose lanes (2). Design Issues A key topic in the design of managed lanes is whether the lane(s) will offer limited access or continuous access. In Jang and Chan (5), an in-depth statistical evaluation of differential safety performance exhibited by these two types of HOV facilities was conducted. When compared with HOV lanes in continuous-access facilities, HOV lanes in limited-access facilities experienced a higher percentage of collisions compared with other lanes, a higher number of total collisions per mile per hour, and a higher number of severe collisions per mile per hour; also, the collision rates measured by traffic volume (per million vehicles travelled) offer the same differential in performance. The differential for left lanes was somewhat different from the pattern for HOV lanes. Compared with left lanes in continuous access facilities, left lanes in limited-access facilities had a higher percentage of collisions and a higher overall collision rate, but a lower rate of severe collisions (5). Cross References Interchanges Guidelines, 12-1 Signing Guidelines, 18-1 Key References 1. AASHTO (2011). A Policy on Geometric Design of Highways and Streets. Washington DC. 2. Chrysler, S.T., & Nelson, A.A. (2009). Driver Comprehension of Managed Lane Signing. (FHWA/TX-09/0-5446-3). College Station: Texas Transportation Institute. 3. McGhee, C.C. (1998). Traffic Control for High Occupancy Vehicle Facilities in Virginia. (VTRC 98-R25). Charlottesville: Virginia Transportation Research Council. 4. Chrysler, S.T., Williams, A.A., & Fitzpatrick, K. (2008). Driver Comprehension of Signing and Markings for Toll Facilities. (FHWA/TX- 08/0-5446-2). College Station: Texas Transportation Institute. 5. Jang, K., & Chan, C.-Y. (2009). High-occupancy-vehicle lane configurations and safety performance of California freeways: Investigation of differential distributions and statistical analysis. Transportation Research Board 88th Annual Meeting Compendium of Papers [CD- ROM]. 15-9 HFG URBAN ENVIRONMENTS Version 2.0

SIGHT DISTANCE CONSIDERATIONS FOR URBAN BUS STOP LOCATIONS Introduction Sight distance considerations for urban bus stop locations refers to sight line issues that stem from the placement of urban bus stops. Bus stop placement and design are dependent on a multitude of factors including vehicle delays, bus delays, pedestrian waiting areas, cost, safety, and others. Two percent of all pedestrian collisions in urban areas occur at bus stops (1), primarily because the bus obstructs the view of oncoming vehicles and the pedestrians who cross in front of the bus. This guideline discusses the issues related to sight distance and visibility at bus stops. Design Guidelines The following guidelines describe issues related to sight distance and driver crash risks for far-side, near-side, and midblock bus stop locations. These issues can be used to identify potential pitfalls when designing bus stops at specific locations (2). Bus Stop Location Sight Distance Issues Driver Crash Risks Far-side Stop May block sight distance for: • Crossing vehicles • Crossing pedestrians May increase rear-end crashes as drivers don’t expect buses to stop on the far-side after stopping at a red light. Near-side Stop May block sight distance for: • Crossing vehicles stopped to the right of the bus • Crossing pedestrians • Curbside traffic control devices Increased conflicts with vehicles turning right. Midblock Stop None Encourages pedestrians to cross midblock. • Bus stops should be located to provide maximum sight distance to all critical roadway elements (1) • Bus stops should not be placed near driveways, on curves or superelevated locations, or on steep grades (1,3). • Bus stops should not be obscured by trees, poles, buildings, signs, etc. (3, 4) • Adequate lighting should be provided at bus stops (3) • Near-side bus bays should be avoided because they are likely to obstruct sight distance to traffic control devices and pedestrians (2) While visibility is enhanced for many of the movements, sight restrictions are still present for left turning vehicles. Source: recreated from Texas Transportation Institute, Texas A&M Research Foundation and Texas A&M University (2) Based Primarily on Expert Judgment Based Equally on Expert Judgment and Empirical Data Based Primarily on Empirical Data HFG URBAN ENVIRONMENTS Version 2.0 15-10

Discussion One of the factors that results in bus collisions with vehicles or pedestrians is the lack of adequate sight distance or sight lines. A review of pedestrian safety research (1) concluded that 2% of pedestrian collisions in urban areas occurred at bus stops. Most of these collisions did not occur between a pedestrian and a bus; rather, the bus created a visual barrier between the approaching vehicles and the pedestrians who crossed in front of the bus. In addition, visual obstructions outside of the bus, such as signs, shrubbery, wide columns, and other obstacles may block the bus operators’ view of pedestrians (4). Bus stops that are poorly located relative to the roadway edge can lead to poor visibility of pedestrians. A bus stop that is set back too far from the curb for the operator to see pedestrians may lead pedestrians to encroach into the roadway in an attempt to be more visible. Finally, a lack of lighting can reduce the visibility of pedestrians both at bus stops and while crossing the street to approach or leave the bus stop. Many factors affect the decision whether to place a bus stop at the near or far side of an intersection, or at midblock. Several studies (e.g., 5, 6) suggest that far-side bus stops can enhance pedestrian safety by eliminating sight distance restrictions associated with the stopped bus, primarily because they make pedestrians more visible to motorists approaching from behind the bus—with these bus stops, pedestrians are encouraged to cross the street behind the bus rather than in front of the bus. Also, far-side stops are less likely to obscure motorists’ view of traffic signals, signs, and pedestrians, and they reduce conflicts between buses and right-turning vehicles (3). However, the number of rear-end crashes may increase because drivers don’t expect buses to stop on the far side after stopping at a red light. Near-side stop locations require alighting passengers to cross the street in front of the bus, which can obscure the sight lines from surrounding vehicles to the pedestrians. Also, the buses can block right-turning motorists’ sight lines to pedestrians or slow-moving vehicles in the cross street. However, near-side stops can be effective where there are not heavy volumes of right-turning vehicles at the intersection. The guidelines in Texas Transportation Institute et al. (2) recommend that bus bays should be avoided for near-side bus stops because they are likely to obstruct sight distance to traffic control devices and pedestrians. The guidance in Metcalf and Bond (3) suggests that, although there are generally no sight distance issues with midblock bus stops, these locations should be used when the use of near-side and far-side stop locations are not feasible due to safety considerations at the intersection other than sight distance. Design Issues Bus stop design should guide alighting passengers to cross the road from behind the bus rather than from in front of the bus, which would enable passengers to see the oncoming traffic (6). In addition, pedestrians and commuters should be guided not to walk near the bus or cross the road by walking near the bus, because it is difficult for bus drivers to see pedestrians in these areas. Some mitigation strategies that improve sight distance and pedestrian visibility encourage commuters to walk in controlled areas that are easier for drivers to see. These mitigations include signing, striping, bus turnouts located such that alighting passengers have a clear view of the approaching traffic, crosswalks, and channelized pedestrian movement to crosswalks. Cross References Sight Distance Guidelines, 5-1 Methods to Increase Driver Yielding at Uncontrolled Crosswalks, 15-2 Key References 1. Campbell, B.J., Zegeer, C.V., Huang, H.H., & Cynecki, M.J. (2004). A Review of Pedestrian Safety Research in the United States and Abroad. (FHWA-RD-03-042). McLean, VA: FHWA. 2. Texas Transportation Institute, Texas A&M Research Foundation, and Texas A&M University (1996). TCRP Report 19: Guidelines for the Location and Design of Bus Stops. Washington, DC: Transportation Research Board. 3. Metcalf, D.D., & Bond, V.L. (2006). Bus stop guidelines to meet urban, suburban and rural conditions. ITE 2006 Technical Conference and Exhibit Compendium of Technical Papers. 4. Pecheux, K.K., Bauer, J.K., Miller, S., Rephlo, J.A., Saporta, H., Erickson, S., Knapp, S., & Quan, J. (2008). TCRP Report 125: Guidebook for Mitigating Fixed-Route Bus-and-Pedestrian Collisions. Washington, DC: Transportation Research Board. 5. Technology & Management Systems, Inc. (2001). TCRP Report 66: Effective Practices to Reduce Bus Accidents. Washington, DC: Transportation Research Board. 6. Pulugurtha, S.S., & Vanapalli, V.K. (2008). Hazardous bus stop identification: An illustration using GIS. Journal of Public Transportation, 11(2), 65-83. 15-11 HFG URBAN ENVIRONMENTS Version 2.0

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TRB’s National Cooperative Highway Research Program (NCHRP) Report 600: Human Factors Guidelines for Road Systems: Second Edition provides data and insights of the extent to which road users’ needs, capabilities, and limitations are influenced by the effects of age, visual demands, cognition, and influence of expectancies.

NCHRP Report 600 provides guidance for roadway location elements and traffic engineering elements. The report also provides tutorials on special design topics, an index, and a glossary of technical terms.

The second edition of NCHRP 600 completes and updates the first edition, which was published previously in three collections.

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