An Intersection Database Facilitates Access to Complex Signalized Intersections for Pedestrians with Vision Disabilities

A growing number of intersections and crosswalks pose barriers to pedestrians with vision disabilities. This project investigated the effects of providing verbal descriptions of intersections and crosswalks on the performance of street-crossing subtasks by individuals who are totally blind. The authors designed an intersection database containing information relevant to crossing sub-tasks such as finding and aligning with the crosswalk, deciding when to cross, remaining in the crosswalk, and recognizing the end of a crossing. The authors conducted an experiment with 22 blind adults at two intersections in Portland, Oregon. The intersections included crosswalks that varied widely in geometric and operational characteristics, including the presence or absence of accessibility features. In the no database condition, participants used their typical street-crossing procedures. In the database condition, participants additionally listened to database-generated descriptions of the intersections and crosswalks before crossing. The database descriptions had significant positive effects on some subtasks (primarily "crossing" subtasks such as deciding when to cross) and not others (primarily "wayfinding" subtasks such as remaining in the crosswalk). Participants' reports of the usefulness of specific features of the database were supported by the empirical findings. Implications of the findings for database development, transportation engineers, blind pedestrians, and orientation and mobility specialists are discussed.