NYMTC Regional Pedestrian Safety Study - New York Metropolitan ...

crashes, the 52 percent is an overstatement of the impact that could be expected in other
locations. (Markowitz, et al., 2006) A more realistic crash reduction factor for countdown
pedestrian signals is 25 percent (NYMTC workshop, 2006). The study also found the meaning of
the countdown was obvious to pedestrians; note that in San Francisco the countdown starts when
the flashing hand would have started. Additional findings were that the number of pedestrians
who were in the intersection when the signal turned red decreased, as did the number of
pedestrians who started running. There was a small (insignificant) decrease in pedestrian/vehicle
conflicts. The shifts in driver behavior that the study noted were not statistically significant.
(Markowitz, et al., 2006)
Other studies were not as positive. In Lake Buena Vista, Florida, Huang and Zegeer (2000)
found that countdown pedestrian signals reduced the number of pedestrians that start running due
to the flashing DON’T WALK signal. However, the number of pedestrians who did not comply
with the Walk phase actually increased. In Berkeley, California, the impact of countdown
pedestrian signals was an increase in pedestrian speeds and a decrease in the number of “late
finishers,” but otherwise there were few changes in pedestrian behavior (PHA, 2005).
Leading Pedestrian Intervals (LPIs) (also known as Advanced Walk Signals): LPIs provide a
head start to the pedestrian signal indicator (often 3 seconds) before the vehicular green phase
starts. NYCDOT uses a six second LPI. By allowing pedestrians to take possession of the
intersection first instead of being intimidated by the turning cars, they clear the intersection
sooner, allowing more time for the cars. Thus, they can improve traffic operations also.
NYCDOT has implemented LPIs at many intersections and has found them well received by the
public. King (1999) found a 12 percent decrease in vehicular-pedestrian crashes after the
implementation of LPI at some New York City intersections. When compared to control sites
and factored for severity, he estimated a 64 percent decrease in crashes.
The LPIs combined with the audible signals are very successful; the audible signal alerts the
pedestrians that the signal has changed, allowing them to take advantage of the early start; this is
particularly valuable where the LPI is only three seconds.
Split Phasing: Split phasing is recommended where there is heavy pedestrian activity. The
green phase is split into two parts. During the first part (which is long enough for pedestrians to
cross the intersection), pedestrians receive protected walk time when vehicles can go straight but
not turn. In the second part of the green phase, vehicles are allowed to turn. See Figure 5.17
below.
NYCDOT found an average reduction of 86 percent in pedestrian-vehicle conflicts after the
implementation of split phasing at 12 midtown Manhattan intersections, as well as a ten percent
decrease in pedestrian crashes, and a reduction of 52 percent in illegal pedestrian crossings. The
reduction in conflicts also had the impact of increasing vehicular speed by 33 percent.
(NYCDOT, 2004)
NYMTC Pedestrian Safety Study 76