Pedestrian Signal Safety - AAA Foundation for Traffic Safety

METHODS
The project objectives were accomplished through the following activities:
• A literature review on topics including the pedestrian walking task, pedestrian signal timing
(especially as it relates to the needs of older pedestrians), pedestrian walking speed, and
pedestrian countdown (PCD) signals.
• A survey of agencies to identify the state of the art and state of the practice in pedestrian signal
timing and the use of pedestrian signals.
• An observational study of pedestrian walking speed and crossing behaviors at four
intersections in each of six jurisdictions equipped with both traditional pedestrian signals (TPS)
and PCD signals.
• A survey of pedestrians at those study sites.
• A traffic operations simulation to determine how the amount of time allocated for pedestrian
intervals affects traffic operations at each intersection.
This chapter discusses how each of these activities was pursued.
LITERATURE REVIEW
To provide background information on safely accommodating older pedestrians at intersections,
recently published literature (within the last 20 years) was reviewed on topics including the pedestrian
walking task, pedestrian signal timing (especially as it relates to the needs of older pedestrians),
pedestrian walking speed, and PCD signals. This literature was identified through searching the
Transportation Research Information Service and the Internet. This chapter provides a summary of
the key findings from that review.
OVERVIEW OF PEDESTRIAN TASK
The pedestrian task for crossing an intersection can be described as including the following
processes: expectation, perception, detection, cognition, selection, action, and reaction. Visual acuity
and color perception are the main processing skills required to make safe judgments about when to
cross the street at a signalized intersection. Reduced visual abilities can be assumed for nearly all
older pedestrians. Reductions in auditory processing, motor functions, and cognition can complicate
the process of crossing at intersections for older pedestrians (Gates et al 2006).
In 1995, Harkey explored the problems of older drivers and pedestrians at intersections. The author
noted that elderly pedestrians (age 75 and older) were overrepresented in both left-turn and rightturn
accidents. The author cited the following potential causes for this overrepresentation: increased
exposure resulting from slower walking speeds; lack of understanding that vehicles may turn during
their WALK interval; inability to react quickly enough to avoid turning vehicles; reduced vision; and too
much reliance on the pedestrian signal alone (Harkey 1995).
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