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Exhibit 48. Nearfar lane effects, pre condition, for PHB crosswalk.
Far-Lane Event
Near-Lane Lane Rolling Stopped Forced X-Able Non-X. Multiple Events
Event Outcome Yield Yield Yield Gap Gap RY STY CG FY non-CG Total
Rolling Yield Utilized 1 4 3 6 1 0 1 1 1 0 18
Non-Utlz. 3 4 0 1 24 1 0 0 0 0 33
Stopped Yield Utilized 2 24 10 21 0 2 4 8 3 0 74
Non-Utlz. 7 6 0 1 19 1 0 0 0 5 39
Forced Yield Utilized 2 4 8 11 0 1 0 3 1 0 30
Non-Utlz. 0 0 0 0 0 0 0 0 0 0 0
Crossable Gap Utilized 8 7 22 82 0 2 2 19 9 0 151
Non-Utlz. 0 1 0 1 17 0 0 1 0 2 22
Non-Cross. Gap Utilized 0 1 1 2 0 0 0 1 0 0 5
Non-Utlz. 6 10 0 13 185 2 0 2 0 13 231
Total 29 61 44 138 246 9 7 35 14 20 603
yields forced by the pedestrian. The analysis of the far-lane 2. Falsely Rejected Crossing Opportunity: Pedestrian
event shows that a majority of the non-utilized yields were "NoGO" in a crossable/safe situation.
attributable to either non-crossable gaps or multiple events in 3. Correctly Rejected Non-Crossable Event: Pedestrian
the far lane. Overall, only 22 events with yields in both lanes "NoGO" in a non-crossable/unsafe situation.
were non-utilized, including yields in the multiple events cat- 4. Falsely Accepted Non-Crossable Event: Pedestrian "GO"
egory, which indicates very good overall judgment of the per- in a non-crossable/unsafe situation.
ceived risk. 5. Inconclusive Event: Pedestrian "GO" in a forced yield
Similarly, of the 22 non-utilized crossable gaps, 19 had non- condition.
crossable gaps in the far lane. In total, pedestrians encountered
28.7% crossable gaps in both the near and far lanes. In the near The first four categories correspond to a classical 2x2 event
lane, 87.3% of crossable gaps were utilized, along with 89.0% matrix that relates the real-world condition to the pedestrian
in the far lane. The crossing opportunity availability and uti- response. The last category applies to events associated with
lization statistics are summarized in Exhibit 49. forced yields. A forced yield may involve some risk if neither
The results in Exhibit 49 can be interpreted as events that driver or pedestrian acts to avoid a collision. However, many
are potential crossing opportunities (in the form of yields and participants appeared to be deliberately forcing yields, which
crossable gaps) and as those that correspond to non-crossable makes it difficult to discern the level of true risk from the data.
gaps. Using this stratification, every cell in Exhibit 49 can be Exhibit 50 summarizes the event classification for the pre
categorized as to whether the pedestrian correctly interpreted study at the RCW crosswalk.
an event (for example, utilized a crossable gap in both lanes) Exhibit 50 suggests that overall, 32.2% of crossings are clas-
or not. Applying this framework to every cell, a total of five sified as correct utilizations of crossing opportunities and
event outcome categories emerge: 49.4% of events were correctly rejected events. Only 4.5%
were classified as missed opportunities and inefficient behav-
1. Correctly Accepted Crossing Opportunity: Pedestrian ior, and 1.0% fell into the potentially risky category (after
"GO" in a crossable/safe situation. O&M interventions were removed from the data). In addi-
tion, 12.9% fell into the inconclusive category and were asso-
ciated with a forced yield in either the near or far lane.
Exhibit 49. Summary of availability and
utilization statistics, PHB crosswalk, pre.
Posttest Blind Pedestrian Behavior
Pre (n = 603) Near Lane Far Lane
at the PHB Crosswalk
Availability Statistics
P(Y_Enc) 32.2% 27.2% With the installation of the PHB, the analysis framework
P(CG_Enc) 28.7% 28.7%
has to be modified from the pre condition. Pedestrians now
encounter a signal indicating that the signal phase is either W,
Utilization Statistics
FDW, or DW. Blind pedestrians hear a locator tone during
P(GO|Y) 62.9% 75.0%
the DW and FDW phases and a speech message during the
P(GO|CG) 87.3% 89.0%
W phase. The appropriate crossing behavior is therefore
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Exhibit 50. Summary of pedestrian behavior, pre condition,
PHB crosswalk.
Pedestrian Crosswalk Condition
Decision Crossable/Safe Non-Cross./Unsafe Inconclusive
GO 194 32.2% 6 1.0% 78 12.9%
NoGO 27 4.5% 298 49.4%
linked to the signal indication, and the analysis of the concur- The results show that almost all of the early crossing events
rent vehicle states becomes a secondary item of interest. that started in "Flashing" or "Solid Yellow" phases were asso-
Exhibit 51 shows the frequency of crossing initiation for the ciated with crossing opportunities. The majority of these were
(blind) pedestrian relative to PHB signal phases. yields in both lanes (68 out of 105 events, or 64.7%), although
The results show that only 36.7% of pedestrians crossed in 52.9% of those were associated with a forced yield in at least
the intended "Walk" phase and that most (39.0%) actually ini- one of the lanes. The rest were some combination of yields and
tiated the crossing just before the "Walk" phase (and the APS crossable gap, with only one exception, where a non-crossable
alert) in the vehicular solid yellow. In other words, they began gap existed in the far lane. No rejected opportunities were
to cross following their pressing the call button but prior to the observed in the two early phases, suggesting great efficiency for
APS message. Further, 11% crossed even earlier, in the vehi- those pedestrians who chose to cross there. However, 57.1% of
cle "Flashing Yellow" phase, and 13.3% didn't cross until the the crossings were associated with a forced yield, which may
"Flashing Don't Walk" phase. Overall, only three times (out of indicate some level of risk depending on pedestrian and driver
208 lane crossings) did pedestrians not cross in the first cross- awareness of the situation.
ing phase and have to reactivate the signal. Events in the "Walk" phase include a significant number of
These figures suggest that the study participants rely heavily rejected events (28.0%), mostly in the form of non-crossable
on their own personal judgment, even with the signal beacon gaps. This suggests that a portion of drivers did not comply
in place. Pedestrians tended not to cross in "Walk" if they were with the signal indication, a pattern that is explored in more
unsure about whether vehicles had in fact stopped. Even when detail later. Some events (4.7%) suggest inefficient behavior
the APS confirmed to the blind pedestrian that a "Red" signal (i.e., failure to cross during "Walk" phase), pointing to uncer-
indication was being presented to an approaching driver, some tainty in crossing for some pedestrians. The 32.7% "inconclu-
would still not cross until they were confident that it was safe sive" events were all associated with forced yields, indicating
to do so. Similarly, they would readily cross before the "Walk" that the pedestrian initiated the crossing before the driver ini-
phase if they perceived a crossing opportunity. To illustrate this tiated the yield. Presumably, these events are acceptable at a
point, Exhibit 52 shows the near and far-lane event outcomes signal; however, there is still some degree of risk if those drivers
(same as pre analysis) by signal phase. had been unaware of the pedestrian action.
Exhibit 51. Blind pedestrian crossings at PHB by signal phase
(% of all crossings).
90
39.0%
80 n = 210 36.7%
70
60
Frequency
50
40
13.3%
30 11.0%
20
10
0
Flashing Yellow Yellow Red Flashing Red
/ Don't Walk / Don't Walk / Walk / Flashing DW
Signal Phase
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Exhibit 52. Near-far lane effects post condition for PHB crosswalk by signal phase.
Phase = Flashing Yellow
Near-Lane Near-Lane Rolling Stopped Forced X-Able Non-X. Multiple Events
Event Outcome Yield Yield Yield Gap Gap RY STY CG FY non-CG Total
Rolling Yield Utilized . . . . . . . . . . 0
Non-Utlz. . . . . . . . . . 0
Stopped Yield Utilized 1 2 2 0 5
Non-Utlz. . . . . . . . . . . 0
Forced Yield Utilized 1 5 4 0. . . . . . 10
Non-Utlz. . . . . . . . . . . 0
Crossable Gap Utilized 0 1 6 1. . . . . . 8
Non-Utlz. . . . . . . . . . . 0
Non-Cross. Gap Utilized . . . . . . . . . . 0
Non-Utlz. . . . . . . . . . . 0
Total 0 2 8 12 1 0 0 0 0 0 0 23
Phase = Yellow
Near-Lane Near-Lane Rolling Stopped Forced X-Able Non-X. Multiple Events
Event Outcome Yield Yield Yield Gap Gap RY STY CG FY non-CG Total
Rolling Yield Utilized 4 4 7 2 0 0 . 0 . . 17
Non-Utlz. . . . . . . . . . . 0
Stopped Yield Utilized 1 14 4 2 1 0 0 22
Non-Utlz. . . . . . . . . . . 0
Forced Yield Utilized 6 5 8 5 0 0 . 0 . . 24
Non-Utlz. . . . . . . . . . . 0
Crossable Gap Utilized 2 4 7 4 0 1 . 1 . . 19
Non-Utlz. . . . . . . . . . . 0
Non-Cross. Gap Utilized . . . . . . . . . . 0
Non-Utlz. . . . . . . . . . . 0
Total 0 13 27 26 13 1 1 0 1 0 0 82
Phase = Walk/Red
Near-Lane Near-Lane Rolling Stopped Forced X-Able Non-X. Multiple Events
Event Outcome Yield Yield Yield Gap Gap RY STY CG FY non-CG Total
Rolling Yield Utilized 4 5 5 2 0 0 1 0 0 . 17
Non-Utlz. 0 2 0 0 4 0 2 0 0 . 8
Stopped Yield Utilized 4 10 2 3 0 0 1 0 0 20
Non-Utlz. 0 1 0 0 1 0 0 0 0 . 2
Forced Yield Utilized 4 3 5 4 0 1 1 1 2 . 21
Non-Utlz. . . . . . . . . . . 0
Crossable Gap Utilized 1 6 5 4 0 0 0 1 2. 19
Non-Utlz. . . . . . . . . . . 0
Non-Cross. Gap Utilized . . . . . . . . . . 0
Non-Utlz. 2 0 0 0 18 0 0 0 0 . 20
Total 0 15 27 17 13 23 1 5 2 4 0 107
Phase = Flashing Don't Walk/Flashing Red
Near-Lane Near-Lane Rolling Stopped Forced X-Able Non-X. Multiple Events
Event Outcome Yield Yield Yield Gap Gap RY STY CG FY non-CG Total
Rolling Yield Utilized 0 3 0 0. 1 0 1 1 . 6
Non-Utlz. . . . . . . . . . . 0
Stopped Yield Utilized 0 4 0 0 0 0 0 1 5
Non-Utlz. . . . . . . . . . . 0
Forced Yield Utilized 0 3 3 2. 1 1 1 1 . 12
Non-Utlz. . . . . . . . . . . 0
Crossable Gap Utilized 1 0 1 1. 0 0 1 1 . 5
Non-Utlz. . . . . . . . . . . 0
Non-Cross. Gap Utilized . . . . . . . . . . 0
Non-Utlz. . . . . . . . . . . 0
Total 0 1 10 4 3 0 2 1 3 4 0 28
