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22 Four variations of the concept of a relocated crosswalk are Remove acceleration lanes: While facilitating the move- presented: ment of traffic exiting the CTL, acceleration lanes are often associated with higher vehicle speeds. Higher vehicle speeds Distal crosswalk: This treatment would relocate the cross- are associated with a decreased likelihood of drivers yield- walk to a distance of approximately 100 ft from the circu- ing and an increased injury rate in the event of a collision. lating lane of the roundabout. The (presumed) benefit is the lower level of ambient noise at the crosswalk that is associ- Signalization Treatments with APS ated with moving the crosswalk further from the circulatory roadway. Driver benefits include reduced queue spillback Signals at roundabouts and channelized turn lanes rep- issues in the roundabout with added storage capacity for the resent a more costly and intrusive treatment for providing exit lane(s). Drawbacks of this treatment include poten- a safe crossing environment for pedestrians. Traffic signals tially longer pedestrian walking distances, depending on may introduce delays to both pedestrians and vehicles. Addi- the origindestination patterns at the site. An additional tionally, depending on signal timing and placements, vehi- drawback is that sighted pedestrians may ignore the distal cle queues can spill back on the roundabout exit from the crosswalk and cross closer to the roundabout unless phys- signal to affect roundabout circulating flow or CTL through ically restricted from doing so. movements. However, APS-equipped signals can be effective Traffic calming at distal location: The distal crosswalk can at stopping traffic and at providing the pedestrian with visual be combined with other treatments to provide some traf- and auditory cues of when the crossing phase is active. CTL fic calming measures to reduce speeds, increase the likeli- signal impacts can be reduced through coordination with hood of drivers yielding, and reduce the risk of collisions. phasing at the main intersection and to avoid the likelihood Potential treatments include lowering regulatory speeds of queue spillbacks onto the through lanes. Pedestrian sig- and the installation of a raised crosswalk. nals with a walk indication can and should be outfitted with Median island at distal location: The distal crossing location an APS to provide auditory cues in addition to the visual sig- would no longer have the benefit of a pedestrian refuge island nal display. since the roadway at that point is most likely undivided. Therefore, a distal crossing would require a one-stage cross- Pedestrian scramble phase: This signal strategy stops all ing of both directions of vehicular traffic. A median island vehicular traffic at the roundabout intersection to allow would provide pedestrian refuge and re-establish a two- pedestrian movements in any and all directions (along stage crossing. marked crosswalks). Pedestrian activation at any approach Offset exit crossing: The potential effectiveness of this of the facility would (following some minimum green time treatment rests on the premise that pedestrians (in partic- for vehicles) produce a red signal at all entry lanes. Follow- ular, blind pedestrians) experience more difficulty crossing ing a clearance interval designed to allow all vehicles in the exit lanes than entry lanes. By offsetting the exit-lane por- circulatory lane to exit the roundabout, a pedestrian walk tion of the crosswalk and creating a zigzag crossing, gap signal would be presented to all pedestrians waiting to cross. selection ability may be facilitated if ambient noise levels This treatment alternative enables pedestrians to cross in are in fact reduced relative to the typical crosswalk loca- a single stage. Following the pedestrian walk phase, vehicles tion. The zigzag configuration would further maintain and at all entry lanes would be given a green signal to proceed. even enforce a two-stage crossing strategy and would pro- While simple in concept and in operation, the effectiveness vide supplemental queue storage at the exit lane. of such a signalization strategy has yet to be determined. This strategy likely has little application to CTLs. The crosswalk modification treatments primarily apply to Pedestrian-actuated traditional signal one or two stage: roundabout crossings. Some special considerations for geo- This treatment uses a traditional traffic signal for pedestri- metric design at CTLs include: ans at (typically) unsignalized locations such as a round- about or CTL. The signals are standard red-yellow-green Add deceleration lanes: The use of deceleration lanes for traffic signal heads that rest in green when no push-button traffic using the CTL has several potential advantages: (1) if activations are in place. The treatment is particularly useful vehicles, in fact, slow down in the deceleration lane, slower for blind pedestrians because the signal provides auditory vehicle speeds can increase the likelihood of drivers yielding information about phase indication via APS, much like they to pedestrians, and (2) when used in conjunction with some are accustomed to from a conventional intersection. In type of audible surface treatment, such a cue may facili- areas with high traffic and/or pedestrian volumes, delay and tate crossing decision-making. queue spillback at roundabouts could be problematic,