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56 Table 9. Participant survey comparison of two-lane roundabout treatments. Less Risky About the More Risky Not Same Risk Answered Pretest (n=18) 3 (17%) 7 (39%) 7 (39%) 1 (6%) PHB (n=13) 7 (54%) 4 (31%) 1 (8%) 1 (8%) RCW (n=13) 3 (23%) 8 (62%) 1 (8%) 1 (8%) As discussed in the previous sections on participant feed- the APS device, only a few said they would wait for the audible back, the participants' suggestions of intersection modifica- "Walk" message (and thereby the "Walk" signal phase). Most tions after their crossings in the pretest may provide additional respondents acknowledged the benefit of the push-button information about their concerns. Some suggested signals, locator tone to identify the crossing locations, but responses even though some of those same individuals said that they were on initial alignment and maintaining alignment during cross- not fans of audible signals, and suggested that it would be good ing were mixed. It needs to be acknowledged here that the if the signal could be used optionally. One suggested a light locator tones were generally too quiet in this installation to be that signaled to motorists that pedestrians were waiting to audible across the width of the street. Therefore, participants cross. Some suggested that detectable warnings needed to be generally couldn't hear the far-side message or locator tone present on both crosswalks (for some reason detectable warn- until a little past the middle of the crossing. The far-side APS ings were only installed on the north crosswalk during pretest). did seem to help people know when they were about to reach One suggested some way to know that it was a roundabout the end of the crosswalk. Some participants negatively com- when approaching as a pedestrian, and another suggested mov- mented on the fact that the push buttons on the island were ing the exit crosswalks further from the roundabout circu- installed on top of a wall used to contain landscaping, which latory roadway. they didn't expect. This part of the installation clearly wasn't In the posttest, participants commented about the uneven ideal and was partly related to the temporary nature of this surface of the raised crosswalk and the need to have a smoother PHB installation. transition. Several made positive comments about the signal and push-button locator tone; one said: "if they're going to use Compliance with Signal Indications locator tones, those were pretty good." At posttest, participants Pedestrian Compliance seemed generally happy with the modifications, particularly the pedestrian hybrid beacon. Several stated that the raised The analysis of pedestrian crossing performance does not crosswalk didn't make a difference, while others felt it made consider an important aspect of the behavior at the PHB: a big difference in drivers' willingness to yield. the signal phase during which pedestrians chose to cross. The Participants in the posttest were also asked several questions analysis results remain valid since they describe pedestrian specific to the PHB, the push-button locator tone, and the actions in terms of actual driver behavior. For example, most audible message (see Table 10). For the questions in the table, drivers are expected to stop before the "Walk" phase comes on. participants were asked to rate the extent of their agreement, Similarly, a "Walk" indication is no guarantee of perfect driver with 1 being strongly disagree and 5 strongly agree. compliance and is associated with a risk of red-light running The responses suggest some hesitation in the expected use events. Consequently, the analysis above initially ignored the and effectiveness of the PHB. While most said they would use signal phase. This also ensures that the results are directly com- Table 10. Participant survey response to PHB installation. Average of Responses (N=10) 1=strongly disagree, Rating Questions 5=strongly agree If there were signals like these, I'd push the button each time I wanted to cross 3.7 If there were signals like these, I would always wait to cross until I hear "walk sign 2.0 is on." These signals helped me know I was coming to the crosswalk. 4.2 These signals helped me align to cross. 2.4 These signals helped me go straight across the crosswalk. 2.4 These signals helped me know I was approaching the end of the crosswalk 3.4
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57 parable to the pretest condition as well as crossing performance APS alert) in the vehicular solid yellow. In other words, they at the RCW crossing. began to cross following pressing the call button but prior to the Nonetheless, the installation of the PHB is associated with audible message. Further, 11% crossed even earlier, during the some legal implications for when pedestrians should cross. At vehicle "Flashing Yellow" phase, and 13.3% didn't cross until the PHB, the vehicle signal display rests in a "Dark" mode the flashing "Don't Walk" phase. Overall, only three times did pending a pedestrian's pressing of the APS push button. While pedestrians not cross in the first crossing phase and have to the language in the MUTCD (FHWA 2009) allows for a PHB reactivate the signal. From anecdotal observation, participants to rest in "Dark" for the pedestrian mode, this was not the case appeared to cross whenever they first heard cars stop. The actual at the tested installation. The pedestrian display for the signal pedestrian signal display at that time seemed to be less impor- rested in "Don't Walk," as a conventional signal would. Conse- tant to the participants. As discussed above, observations fur- quently, pedestrians were expected to push the button and wait ther suggested that driver deceleration behavior was more rapid to cross until the onset of the "Walk" phase. In this project, par- and the stop location was closer to the crosswalk, which seemed ticipants were informed of the phase sequence and intended to make these yields more distinguishable for the blind par- behavior. However, they were always instructed to "cross when ticipants. It is re-emphasized here that participants were not they are ready" and to "rely on their own judgment" when mak- instructed that they had to cross during the "Walk" phase. ing crossing decisions. Participants were not given any specific These findings suggest that the study participants rely heav- information regarding the legal issue of beginning crossing ily on their own personal judgment, even with the signal beacon during "Walk" at pedestrian signals. In other words, pedestri- in place. Pedestrians tended not to cross in "Walk" if they were ans were not told that they had to cross in the "Walk" phase. unsure about whether vehicles had in fact stopped. Even when With the PHB, pedestrians encountered a signal indicating the audible message confirmed to the blind pedestrian that a that the signal phase is either "Walk" (W), "Flashing Don't "Red" signal indication was being presented to an approaching Walk" (FDW), or "Don't Walk" (DW). Blind pedestrians heard driver, some would still not cross until they were confident that a push-button locator tone during the DW and FDW phases it was safe to do so. Similarly, they would readily cross before and a speech message during the W phase. Figure 21 shows the "Walk" phase if they perceived a crossing opportunity. the frequency of crossing initiation for the (blind) pedestrian relative to PHB signal phases. More details on the PHB phase Driver Compliance sequence and timing parameters were given in Chapter 3. The results show that only 36.7% of pedestrians crossed in In the evaluation of the PHB, an important question of inter- the intended "Walk" phase and that many (39.0%) actually est to traffic engineers is the behavior of drivers relative to the initiated the crossing just before the "Walk" phase (and the signal phases. In particular, the PHB is intended to reduce 45 90 39.0% 40 80 n=211 36.7% 35 70 Percentage of Events Frequency of Events 30 60 25 50 20 40 13.3% 15 30 11.0% 20 10 10 5 0 0 Flashing Yellow Yellow Red / Walk Flashing Red / Flashing Don't Walk Signal Phase This figure shows a bar chart of pedestrian crossing behavior in regard to the four PHB signal displays: "Flashing Yellow/Don't Walk," "Yellow/Don't Walk," "Red/Walk," and "Flashing Red/Flashing Don't Walk." The results are discussed in the text. Figure 21. Blind pedestrian crossings at PHB by signal phase (% of all crossings).