Development of an Intersection Prioritization Tool for Accessible Pedestrian Signal Installation

Abstract

Although increased complexity in intersection design and signal timing has improved intersection service to vehicle traffic, it has created additional challenges to pedestrians who are blind or who have low vision. Safe and independent crossings for pedestrians who are blind or who have low vision may require installation of accessible pedestrian signals (APSs) at some complex signalized intersections. APSs provide an audible and sometimes a tactile indication when the walk signal is on to cross the street. The goal of this study was to create a tool to prioritize locations for the installation of APS. To develop the prioritization tool, various characteristics of the intersection and the individual crosswalk were assigned point values that indicated their relative effect on the need for an APS at the crosswalk. For example, a point is assigned if the crossing is interrupted by a median; two points are assigned if there is a channelized turn lane. Field tests were conducted in which sites were ranked in order of their need for APS. The rankings were done separately by transportation engineers using the prioritization tool and by expert judgment of orientation and mobility specialists and pedestrians with visual impairments. The point values of the prioritization tool were modified on the basis of the expert judgment rankings. The final calibrated tool provides practitioners with the means to take observable characteristics of a pedestrian crossing and produce a score that reflects the relative crossing difficulty for pedestrians who are blind, thus enabling prioritization of APS installations.