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 subtasks 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.

Blind and sighted pedestrians' road-crossing judgments at a single-lane roundabout.

OBJECTIVE: The aim of this study was to evaluate the relative risk and efficiency of road crossing experienced by blind and sighted pedestrians at a single-lane roundabout with two levels of traffic volume and at two distances from the roundabout. BACKGROUND: With the rapid spread of modern roundabouts across the United States,their accessibility to blind pedestrians has become an important concern. To date, accessibility research relevant to blind pedestrians has focused on multilane roundabouts, and single-lane roundabouts have been virtually ignored. METHOD: Blind and sighted participants made judgments about when they would cross a single-lane roundabout with high and low traffic volumes, at exit and entry lanes, and at the actual crosswalks and at locations farther from the roundabout. RESULTS: Relative to sighted participants, blind participants' judgments about when to cross were more frequently risky, especially when traffic volume was high. Blind participants also were slower to make crossing judgments and accepted fewer crossing opportunities. Both groups made somewhat safer and more efficient judgments at locations farther from the roundabout. CONCLUSION: Some single-lane roundabouts may pose greater risk to blind pedestrians than to sighted pedestrians, especially when traffic volume is high. Crosswalk location merits further investigation as a design issue. APPLICATION: These findings are relevant to transportation planners and engineers who are responsible for the accessibility of public rights-of-way.