Supporting Material to NCHRP Report 674 (2011)

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APPENDIX B: Long List of Treatments This Appendix contains detailed information about the long list of treatments considered in project NCHRP 3-78a. 4

Appendix B: Long List of Treatments State-of-the-Art Pedestrian Crossings Over the years, a number of various types of pedestrian crossing treatments have been developed to help accommodate safe crossings at various facility types. The team identified a long list of treatments that may be considered for any type of pedestrian crossing, and later identified (through an internal survey) the treatments likely to have the most positive impact on visually impaired pedestrians ability to detect available yields and gaps. This appendix describes the available list of pedestrian crossing treatments that were considered as part of this research project in six basic categories: 1) Driver Information Treatments 2) Traffic Calming Treatments 3) Pedestrian Information Treatments 4) Crosswalk Geometry Modification 5) Signalization with APS 6) Grade Separation The categories function is to group like treatments based on their intended effect on vehicle operations. Each category and the included treatments are described in more detail below. Driver Information Treatments Recent research conducted by Fitzpatrick et al indicates that the use of static pedestrian signs alone is not likely to generate a high frequency of yielding drivers. This is even more likely when low levels of pedestrian volume are present at a crosswalk. This is not to say that signing is ineffective and should not be required. Instead, several recommendations for improvement are possible over static signs, each summarized below. Continuous Flasher. Flashing amber lights are installed on overhead signs, in advance of the crosswalk, or on signs at the entrance of a crosswalk to make it more visible to drivers. The continuous flasher is a static device that operates in a flashing mode independent of whether a pedestrian is at the crosswalk or not. They can utilize a single beacon, or even use multiple beacons in a ‘wig-wag’ configuration. An example of a single solar powered flashing beacon application is shown in Exhibit 1. Flashing beacons are typically installed at uncontrolled intersections when used for pedestrian crossings; however, they are frequently used for signalized intersection applications with horizontal or vertical curve sight distance issues. If medium to high pedestrian volumes are not present at a crosswalk, this treatments effectiveness likely reduces as drivers ignore the beacon because its warning is typically communicating unreliable information. This could lead to driver inattention and insensitivity to the treatment over time. The costs of flashing beacons, including labor, can run approximately $10,000 to $40,000 per crossing dependent on the placement and type of application (Fitzpatrick et al., 2006). 5

Appendix B: Long List of Treatments s Exhibit 1 – Solar Powered Flashing Beacon (courtesy of PTL Solar, http://www.ptlsolar.com/) In-Roadway Warning Sign. Warning signs placed in the street are becoming increasingly popular where sign visibility along the roadside is particularly problematic or when existing signage is ignored. The signs specified by in the Manual of Uniform Traffic Control Devices (MUTCD 2003) and shown in Exhibit 2 read “State Law, Yield to Pedestrians” or “State Law, Stop for Pedestrians.” The sign should be placed in an island if possible to reduce the need for ongoing maintenance as the sign is struck by cars passing over the solid line or snowplows during winter months. Breakaway supports are used if the sign is placed directly in the roadway, and many signs are actually able to be traversed at slow moderate speeds. Speed reductions associated with slight increases in driver compliance are expected with this type of treatment. The costs of the treatment and labor are minimal at best compared to many other treatments. Exhibit 2 – In-Road Pedestrian Crossing Signs (MUTCD 2003) Active When Present Flasher. This treatment is similar to the continuous flasher; however, it is dynamically operated by activation of a pedestrian push button or via automated (passive) 6

Appendix B: Long List of Treatments means such as infrared, microwave, video, or tactile detection. The dynamic push button activated beacon serves to increase conspicuity of the static pedestrian sign. The treatment typically takes the form of a flashing beacon on the roadside, mounted overhead, or imbedded in the pavement (Exhibit 3). Exhibit 3 – Active When Present Flasher and In-Roadway Flashers (Fitzpatrick et al., 2006) Adding language (displayed to the driver) to the sign could be considered. Beacons with detection devices are slightly more costly than the static continuous flashers described previously and include additional costs of approximately $2000 per unit for an APS device. Other automated detection could cost significantly more depending on the complexity of the detection devices used. In addition, if in-roadway warning lights are imbedded in the pavement instead of flashing beacons on the side of the road, these are more expensive and may require significantly more effort to install. In-roadway flashers could be considered if sight obstructions to the side of the roadway are problematic or if flashers are ignored all together. Traffic Calming Treatments Traffic calming is a method of designing streets using visual or physical cues to encourage drivers to reduce speeds. Traffic calming is largely self-enforcing in that the design of the roadway should result in the desired outcome of reduced speeds and aggressive driving behavior. Traffic calming can be a very effective tool at reducing the severity and frequency of crashes, and even noise levels. In addition, studies suggest (Geruschat and Hassan, 2005) that drivers are more likely to yield to pedestrians when traveling at slower speeds. Three possible treatment alternatives aimed at reducing vehicle speeds are described below. Posting Lower Speeds (15 and 25 mph). Reducing regulatory posted speed limits significantly at roundabout and CTLs was a consideration of the team. The primary advantage of this treatment is that it is a low cost traffic calming treatment which is highly dependent on the upon driver compliance. If the design of the roundabout does not encourage slower speeds (i.e. poor geometry), the driver compliance of speeds can only be achieved through heavy 7

Appendix B: Long List of Treatments enforcement of the crosswalk. Posting lower speeds is typically not advisable since the roadway should operate at the design speed intended for the facility. A lower posted speed for a CTL is impractical since it would also apply to the mainline. Raised Crosswalk. A raised crosswalk will reduce vehicle speeds as a function of its height relative to pavement surface and the transitional slope. A low and a gently sloping raised crosswalk would likely have higher speeds as vehicles easily maneuver over the crosswalk. An example of a raised crosswalk in Golden, CO is provided in Exhibit 4. Likewise, a steep incline to a high raised crosswalk could have significant speed reductions; however, the reduced lane capacity may outweigh the benefit of the reduction in speed. Raised crosswalks also introduce vertical obstructions for ambulances and snow plows that need to be considered. Exhibit 4 – Raised Crosswalk in Golden, CO Pedestrian Information Treatments This functional category utilizes treatments that provide pedestrians with audible information that can be used to make more informed decisions about when to safely cross using available yields and/or gaps. It should be noted that some treatments in this functional category have not been fully developed at this time, but were still considered as a possibility as the team developed the research plan. The four possible treatment categories are: Surface Alterations/Rumble Strips. Roadway surface alterations, such as rumble strips, generate auditory cues of approaching and/or yielding vehicles (Inman, Davis, and Sauerburger, 2005). The treatment can also have the added benefit of providing information on the availability of crossable gaps. As an added benefit, the driver may be more cautious when approaching the crosswalk due to the additional sound cue provided by the treatment. Rumble strips can be adhered to the pavement or milled into the pavement. Exhibit 5 shows a rumble strip application in Charlotte, NC. 8

Appendix B: Long List of Treatments Exhibit 5 – Rumble Strip Application in Charlotte, NC Yield Detection System. The use of in-road sensors or video image processing to detect whether vehicles have yielded (stopped or slowly rolling) has shown promise in initial tests completed under a related NIH grant (NIH 2010). An auditory signal provides a speech message to the pedestrian indicating when a vehicle has yielded. The functional problems of such a system are primarily based on reliability of detecting yields that roll very slowly, queued vehicles stopped over the crosswalk (at the entry for instance), and providing an instantaneous cancelling detector in the event a yielded vehicle begins moving again. Work is still underway to improve the system in these three areas. The equipment needed to utilize such a system includes multiple video detection cameras, a signal controller, and APS devices. Such a system would cost approximately $50,000 to $60,000 to implement an entire roundabout or intersection. Alternatively, inductive loops could be utilized if done appropriately; however, there is still work underway to learn the best placement of loops for such a system. Gap Detection System. It is possible to use in-road sensors or video image processing to detect if there is an approaching vehicle (or no vehicle) within some predetermined safe crossing time or distance from the crosswalk. As with yield detection, the use of an auditory signal via an audible device is imperative to provide a speech message to the pedestrian indicating when it is safe to cross. The ability to sufficiently or accurately detect such gaps at roundabout (especially the exit approach) and channelized turn lanes is not known at this time, but is under development (NIH 2010). Yield + Gap Detection System. This treatment would combine the two previous treatments to take advantage of the yield and gap detection capability that could ultimately be possible. It is not known at this time whether such a system is even plausible since there has been no development of gap detection for pedestrian crossing treatments completed at this time. 9

Appendix B: Long List of Treatments Crosswalk Geometric Modification There is the possibility of a modified crosswalk location or an alternative crossing location at roundabouts. This approach would displace all or parts of the crosswalk further away from the circulating lane to separate pedestrian-vehicle interaction from vehicle-vehicle interaction at the roundabout. Supplemental treatments such as static signing, pedestrian-activated signs, and traffic calming techniques can all be applied in the distal crosswalk situation to further enhance accessibility. Four variations of the concept of a re-located crosswalk are presented: Distal Crosswalk. This treatment would relocate the crosswalk to a distance of approximately 100 feet from the circulating lane of the roundabout. The (presumed) benefit is the lower level of ambient noise at the crosswalk that is associated with moving the crosswalk further from the circulatory roadway. Driver benefits include reduced queue spillback issues in the roundabout with added storage capacity for the exit lane(s). Drawbacks of this treatment include potentially longer pedestrian walking distances, depending on the origin-destination patterns at the site. An additional drawback is that sighted pedestrians may ignore the distal crosswalk and cross closer to the roundabout unless physically restricted from doing so. Traffic Calming at Distal Location. The distal crosswalk can be combined with other treatments to provide some traffic calming measures to reduce speeds, and to increase the likelihood of drivers yielding and reduce the risk of collisions. Potential treatments considered include lowering regulatory speeds and the installation of a raised crosswalk. Median Island at Distal Location. The distal crossing location would no longer have the benefit of a pedestrian refuge island, since the roadway at that point is most likely undivided. Therefore, a distal crossing would require a one-stage crossing of both directions vehicular traffic. A median island would provide pedestrian refuge and re-establish a two-stage crossing. Offset Exit Crossing. The potential effectiveness of this treatment rests on the premise that pedestrians (in particular, blind pedestrians) experience more difficulty crossing exit lanes than entry lanes. By offsetting the exit-lane portion of the crosswalk and creating a zig-zag crossing, gap selection ability may be facilitated if ambient noise levels are in fact reduced relative to the typical crosswalk location. The zig-zag configuration would further maintain and even enforce a two-stage crossing strategy and would provide supplemental queue storage for vehicles at the exit lane. Exhibit 6 shows an example of an offset crosswalk. 10

Appendix B: Long List of Treatments Exhibit 6 – Offset (“Zig-Zag”) Crosswalk Design The crosswalk modification treatments primarily apply to roundabout crossing. Some special considerations for geometric design at channelized turn lanes include: Deceleration Lanes. The use of deceleration lanes for traffic using the channelized turn lane has several potential advantages: (1) if vehicles, in fact, slow down in the deceleration lane, slower vehicle speeds can increase the likelihood of drivers yielding to pedestrians, and (2) when used in conjunction with some type of audible surface treatment, such a cue may facilitate crossing decision-making. Acceleration Lanes. While facilitating the movement of traffic exiting the channelized turn lane, acceleration lanes are often associated with higher vehicle speeds. Higher vehicle speeds are associated with a decreased likelihood of drivers yielding and an increased injury rate in the event of a collision. Adoption of a midpoint crosswalk standard serves to move the point at which pedestrian and vehicle paths intersect at a point where the speed of the turning/exiting vehicle is likely to be minimized, before speeding up in the acceleration lane. Signalization Treatments with APS Signals at roundabouts and channelized turn lanes represent a more costly and intrusive treatment for providing a safe crossing environment for pedestrians. Traffic signals may introduce delays to both pedestrians and vehicles. Additionally, depending on signal timing and placement, vehicle queues can spill-back in roundabout exit from the signal to affect roundabout circulating flow or CTL through movements. CTL signal impacts can be reduced through coordination with phasing at the main intersection and to avoid the likelihood of queue spillbacks onto the through lanes. Pedestrian signals with a WALK indication can and should be outfitted with an Accessible Pedestrian Signals (APS) to provide auditory cues in addition to the visual signal display. The signalization category considers the use of traditional signals and pedestrian hybrid beacons. Note: Signals that do not provide a hot (almost immediate) response can frustrate pedestrians and lead them to cross away from the signal or begin crossing as soon as there is a gap in traffic, potentially making motorist stop for no reason and 11

Appendix B: Long List of Treatments lead to future non-compliance; thus a hot response should be provided whenever feasible and practical. If signal coordination is necessary, this may not be possible because this would cause unexpected stopping of vehicles traveling in progression. Pedestrian Scramble Phase: This signal strategy stops all vehicular traffic at the roundabout intersection to allow pedestrian movements in any and all directions (along marked crosswalks). Pedestrian activation at any approach of the facility would (following some minimum green time for vehicles) produce a red signal at all entry lanes. Following a clearance interval designed to allow all vehicles in the circulatory lane to exit the roundabout, a pedestrian ‘WALK’ signal would be presented to all pedestrians waiting to cross. This treatment alternative enables pedestrians to cross in a single stage. Following the pedestrian walk phase, vehicles at all entry lanes would be given a green signal to proceed. The effectiveness of such a signalization strategy, while simple in concept and in operation, has yet to be determined. This strategy has no application to CTLs because the pedestrian movements do not conflict with any other vehicles outside the CTL approach. Exhibit 7 shows a time lapsed picture of a pedestrian scramble phase over an entire day. Exhibit 7 – Time lapse of a pedestrian scramble phase over a 24-hour period in Toronto, Canada (www.spacing.ca). Pedestrian Actuated Traditional Signal – One or Two Stage: This treatment utilizes a traditional traffic signal for pedestrians at (typically) unsignalized locations such as a roundabout or channelized turn lanes. The signals are standard red-yellow-green traffic signal heads that rest in green when no push button activations are in place. The treatment is particularly useful for blind pedestrians because the signal provides auditory information about phase indication via APS, much like they are accustomed to from a conventional intersection. In areas with high traffic and/or pedestrian volumes, delay and queue spillback at roundabouts could be problematic, especially with false (unused) pedestrian actuations. Also, because the signals rest in green the majority of the time, it is possible that drivers may react slowly (or not at all) to the red stop indication. Pedestrian Hybrid Beacon (PHB) – One or Two Stage: The Pedestrian Hybrid Beacon (or HAWK signal) aims to be more efficient than a conventional signal by allowing vehicular traffic to move 12

Appendix B: Long List of Treatments during the pedestrian flashing don't walk phase. When the push button is pushed a flashing yellow starts followed by a solid yellow and solid red. The solid red phase is the beginning of the WALK phase, which last approximately 4 to 7 seconds before a flashing red indication is shown. The flashing red indication for drivers allows traffic to proceed after stopping if the no pedestrian is in the crosswalk. This phasing scheme allows for less vehicular delay while providing similar pedestrian related benefits of a regular signal. A photo of a PHB installation from Tucson, AZ is provided in Exhibit 8. Exhibit 8 – Pedestrian Hybrid Beacon – Note the reverse dog-house signal head that houses the two red indications and the yellow indication. The two lenses at the top of the signal head are red and flash back and forth during the clearance interval. The yellow lens is located on the bottom of the signal head. (Tucson, DOT) The cost of PHB signals is high, costing approximately $75,000 - $100,000 per crosswalk, depending on the width of the street and the length of mast-arm poles. Operation costs are estimated to be $2,000 per year. Driver education may be required for the alternating flashing red signals; drivers are more likely to stop for a familiar control device such as a traffic signal. Most state laws require drivers to treat dark signals other than ramp meters like a four-way stop, so drivers may stop unnecessarily when the signal is dark. A re-configured signal is currently in development to reduce driver confusion about dark signals. However, HAWK signals seem to be effective. According to an eight-month study conducted by the City of Tucson, the HAWK Signals increased driver compliance from 30 to 93 percent. Distal Pedestrian Actuated Signal – One or Two Stage: Entry lane and exit lane pedestrian- activated signals used at a distal crosswalk location or in a zig-zag configuration could be used to establish a one or two-phased pedestrian crossing that maximizes the storage capacity of the exit lane during a vehicle red phase. If a two-phase crossing is utilized, a median refuge island would be necessary. Depending on pedestrian route patterns, these configurations may result in an increase in the travel time for pedestrians compared to a crossing at the traditional splitter island. 13

Appendix B: Long List of Treatments Distal/Zig-Zag PHB – One or Two Stage: The PHB could also be utilized at a distal location or in a zig-zag arrangement, combining advantage of the extra queue storage capacity at the exiting approach of the roundabout with more efficient signal phasing. Depending on pedestrian route patterns, these configurations may result in an increase in the travel time for pedestrians compared to a crossing at the traditional splitter island. The location of the distal crosswalk requires a median refuge island to be utilized if a two stage crossing is necessary. Grade Separated Crossing Grade separation allows pedestrians to operate in an uninterrupted flow without affecting the movement of vehicles. Grade separated facilities must accommodate all persons, including those with vision and mobility impairments. To accommodate all users, these treatments may require very long ramps or elevators. Because of the nature of grade separation, it should only be used as a last resort effort because of the high costs associated with construction of the facilities. Grade separation is typically used in extreme cases where pedestrian must cross very busy streets or freeways, and where pedestrian volumes are extraordinarily high. Grade separated facilities should not be considered where opportunities for crossing at the street level are available on a regular basis because it discourages use of the facility. Pedestrian Overpass. An overpass is typically used where the topography allows for a smooth transition such that stairs, ramps, and other various facilities must be installed to make them accessible to all pedestrians. Overpasses should be designed so that they provide the ability for multiple users to pass by or around each other. This treatment is only reserved for ‘extreme’ pedestrian and vehicle volumes due to the high cost of constructing such a facility. This treatments primary advantage is the elimination of conflicts between vehicles and pedestrians through grade separation. However, it is not a very realistic treatment for roundabouts and CTLs being implemented in the US. Exhibit 9 shows an example of a pedestrian overpass over a heavily traveled roadway. Exhibit 9 – Offset (“Zig-Zag”) Crosswalk Design Pedestrian Underpass. A pedestrian underpass is a rare treatment that is typically used when a smooth transition is not possible at an overpass, or when it is thought of ahead of time during the design and construction process. Underpasses installed as a retrofit require costly underground construction by tunneling. Underpasses may be difficult to keep clean and safe, 14

Appendix B: Long List of Treatments but with proper design and lighting these preconceptions can be overcome. Some countries such as Germany use this design more than others. An example of a German underpass at a roundabout facility is provided in Exhibit 10. Exhibit 10 – Pedestrian Underpass Facility - Germany (Photo by Werner Brilon) 15