Using a Smartphone App to Assist the Visually Impaired at Signalized Intersections


Chen-Fu Liao

August 2012

Report no. CTS 12-25

The blind and Visually Impaired (VI) rely heavily on walking and public transit for their transportation needs. A major challenge for this population is safe crossing of intersections. As a result of the American with Disabilities Act (ADA), Accessible Pedestrian Signal (APS) systems at signalized intersections have improved significantly since 2000. However, these systems still have shortcomings for both users and municipalities, and new approaches are needed to adequately serve pedestrians with low vision. As part of our ongoing effort to develop a prototype Mobile Accessible Pedestrian Signal (MAPS) application for the blind and VI, we interviewed ten blind and lowvision people to better understand what types of information they use at intersection crossings and to identify information types that could assist them. With these survey results, a MAPS prototype was developed that provides signal and intersection geometry information to Smartphone users at signalized intersections. User interaction is via simple tactile input (single or double-tap) and Text-To-Speech (TTS) technology. A MAPS prototype was developed and tested to evaluate the functionalities of providing signal and orientation information to the visually impaired travelers at signalized intersections. This proposal will build upon the developed MAPS and investigate how blind and low-vision individuals gain their spatial knowledge surrounding an intersection and how the MAPS can be used to support their decision-making strategy at intersection crossings.

Download or order

Download PDF (1.29 MB)

Sponsored by:

ITS Institute (RITA)