Transportation and mobility are key to quality of life, equity of opportunity, and economic well-being in urban environments. Yet for travelers with disabilities, navigation along city streets and access to public transportation present significant challenges and often impose severe limits on freedom of movement and the ability to accomplish normal daily activities. To explore the role of technology in addressing these challenges, the Federal Highway Administration established the Accessible Transportation Technologies Research Initiative (ATTRI).

One focus of the ATTRI program is the problem of safe intersection crossing. “For a pedestrian who is vision impaired, navigating intersections poses a particularly daunting task,” says Mohammed Yousuf, the director of the Federal Transit Administration’s Office of Infrastructure and Innovation, and formerly the program manager for ATTRI at FHWA.

Most frequently, the pedestrian must rely on the directional sounds of traffic to first orient him or herself to the intended crossing direction and then to determine when it is time to cross. These decisions can be facilitated in situations where other pedestrians are present or if the intersection is equipped with accessible pedestrian signals, which provide audible and vibrotactile cues. In the absence of such cues when crossing unfamiliar intersections, a common strategy for a pedestrian who has a vision impairment is to remain at the intersection for one or more cycles of the traffic signal phases in order to acclimate and understand traffic patterns sufficiently before making a move to cross. Once a decision is made to cross, the pedestrian generally moves as quickly as possible, using cues such as the crown of the road at the middle of the crossing to gauge progress. Despite his or her best efforts, the safety of a pedestrian with a vision impairment often depends on the alertness and accommodation of the drivers of oncoming vehicles.

For pedestrians who have a mobility impairment, the basic challenge is getting across the intersection in the time that is allocated by the traffic signal control system, and, again, safety often depends on the patience of the drivers of waiting vehicles as the traffic signal changes phases.

“For pedestrians with a combination of disabilities,” says Yousuf, “the situation is even worse.”

To help address these challenges, Carnegie Mellon University, with funding from ATTRI, developed PedPal, a mobile smartphone application that enables pedestrians to communicate directly with signalized intersections and to influence traffic control decisions to their advantage. PedPal combines emerging connected vehicle communication technology with a recently developed real-time, adaptive traffic signal control system to provide for a safer and more efficient intersection crossing experience for pedestrians with disabilities.

Read more at Public Roads Magazine!