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136 Exhibit 59. O&M interventions for PHB crosswalk. O&M Interventions PHB Crosswalk Pre Frequency # of Crossings Percent Entry 5 144 3.5% Exit 2 144 1.4% Overall 7 288 2.4% Post Entry 0 104 0.0% Exit 0 104 0.0% Overall 0 208 0.0% 40 crossings (for example two crossings a day over 4 weeks to the signal phases is intended to capture driver understand- with 5 working days per week). However, given that inter- ing of and compliance with the signal indication. Second, the ventions are very rare events, it is unlikely that the post inter- impact of the PHB installation on pedestrian-induced vehicle vention is an absolute zero, but rather is small enough to where queues at the crosswalk is examined. it was not measurable at the given sample size. Driver understanding of and compliance with the PHB can Exhibit 60 explores the distribution of interventions by sub- be evaluated by relating the driver stopping behavior to the ject and by time of day. Subjects who didn't return for the post indicated signal phase. Exhibit 61 shows a summary of 426 vehi- experiment are shown with negative intervention rates to dis- cle events that were observed during and just after the trial as a tinguish them from participants with zero interventions. The function of PHB signal phase. The exhibit shows the number intervention rates show no trend by time of day. The figure of drivers who yielded (rolling or stopped yield) in each of makes evident that several participants didn't experience any five signal phases: "Blank," "Flashing Yellow," "Solid Yellow," interventions even in the before case at the given sample size "Solid Red," and "Flashing Red." It then relates all vehicle of 16 lane crossings. Given the rare nature of the intervention events to the phase that was active when the vehicle crossed measure, a zero rate should not be interpreted as a perfectly the plane of the crosswalk. The exhibit further contains a safe crossing. record of all vehicles that did not yield. The results in Exhibit 61 show that many drivers who encountered a pedestrian at a crosswalk yielded even before Driver Behavior at the PHB the signal was activated, while others didn't stop at all, even In the evaluation of the PHB, an important question of when the signal was in the solid red phase. The events include interest to traffic engineers is the effect of the signal on vehicle all drivers who in some way interacted with the PHB signal or traffic flow. The driver behavior analysis described herein has the pedestrian. The exhibit does not include any events that two main components. First, the behavior of drivers relative occurred before the signal was activated or after the trial was completed. Exhibit 62 plots two categories of driver behavior for each signal phase: (1) vehicles stopped or stopping, and Exhibit 60. O&M interventions by subject and by (2) vehicles proceeding through the crosswalk. time of day. The exhibit shows that 34.1% proceeded through the cross- PHB walk in "Flashing Yellow," which is permitted behavior. As the 20.0% signal changes to solid yellow, still 11.4% of drivers proceed PRE through the crosswalk, which is allowable if the vehicles were 15.0% too close to the crosswalk to come to a stop. However, even dur- POST O&M Interventions ing the "Solid Red," 12.6% of observed vehicles proceeded 10.0% through the crosswalk. This figure is a concern, since drivers are legally required to stop for the red signal indication and because 5.0% pedestrians expected a crossing opportunity. Driver behavior during "Flashing Red" shows that almost half of the drivers 0.0% (48.2%) remained stopped, suggesting some inefficiency in 1 3 6 9 11 16 4 7 10 12 14 17 2 5 8 13 15 18 driver behavior in response to the PHB. -5.0% The second part of the analysis focuses on the impact of the 9:00am 11:30am 3:30pm PHB installation on vehicle queues. Exhibit 63 shows the sta- Subject tistics for the maximum vehicle queue lengths in the pre and

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137 Exhibit 61. Vehicle events by yielding and stopping phases at PHB. Yielding Vehicles and Phase Yielding Is Initiated Non- Yielding Signal Phase Blank Flash Y Solid Y Solid R Flash R TOTAL Vehicles Crossing Phase Flash Yellow 3 2 5 39 Solid Yellow 3 2 0 5 15 Solid Red 6 3 4 0 13 15 Flash Red 20 20 31 15 15 101 72 Blank 13 18 41 36 53 161 n/a TOTAL 45 45 76 51 68 285 141 Total Vehicle Events 426 Exhibit 62. Evaluation of driver behavior at PHB. 100% 11.4% 12.6% 90% 34.1% 80% Proceeding 51.8% through 70% Crosswalk 60% 50% 88.6% 87.4% 40% 65.9% 30% Stopped or 48.2% 20% Stopping 10% 0% Flash Yellow Solid Yellow Solid Red Flash Red Signal Phase post conditions. The maximum queue length was defined as was observed between queues in the inside and outside lanes. the longest pedestrian-induced queue length that was observed Vehicle queue statistics are shown separately for entry and during or just after a pedestrian crossing. Queues were mea- exit lanes. sured relative to the crosswalk and therefore do not include Exhibit 63 shows that the average maximum queue length additional vehicles that were waiting to enter the roundabout increased from 2.3 to 5.0 vehicles at the entry and from 1.5 to downstream of the crosswalk (at the entry). Vehicle queues 3.9 vehicles at the exit over both approach lanes. The increases are combined for both lanes since no significant difference in average maximum queues are significant at p < 0.0001. With available queue storage of two vehicles (one per lane) at the exit leg, it is evident that the maximum queue sometimes Exhibit 63. Maximum queue length statistics for spilled back into the circulating lane, although the average PHB installation. queue is expected to be less than the reported max queue. The Maximum Vehicle Queues for Both Lanes (in Vehicles) queue spillback effect is also evident in Exhibit 64, which shows Pre Avg. Min. Max. Std. Dev. the cumulative distributions of maximum queue lengths. The Entry (n = 104) 2.3 0.0 10.0 2.4 dashed line in Exhibit 64b represents the available queue stor- Exit (n = 104) 1.5 0.0 9.0 1.8 age at the exit leg. Total (n = 208) 1.9 0.0 10.0 2.1 Exhibit 64 shows a shift in the cumulative queue distribu- Post tion toward higher queues associated with the installation of Entry (n = 104) 5.0 0.0 19.0 3.9 the PHB. The largest effect is a significant reduction in the Exit (n = 104) 3.9 0.0 18.0 3.0 occurrence of zero queues in the post condition, which results Total (n = 208) 4.4 0.0 19.0 3.5 in the large discrepancy at queue length equal to zero. However,