Information Requirements of Pedestrians with Vision Disabilities
In a review of accessible pedestrian signal devices, Bentzen and Tabor (12) provide a high level analysis of intersection information requirements of pedestrians who are blind. Requirements include identification of the sidewalk or roadway path, detection and identification of the intersection, and detection that the intersection is a roundabout. Although the accessibility of roundabouts depends on meeting a large number of information requirements, this report focuses only on requirements related to the availability and detectability of gaps in traffic.
In the absence of traffic signals, the pedestrian would need to either detect that no vehicles are approaching, or that vehicles are yielding in all lanes. Previous research has shown that at many roundabout crossings a substantial number of drivers fail to yield to apparently blind pedestrians (4) (5). Additional regulatory signage had only a small effect on driver yielding (4). Furthermore, research has shown that when vehicles do yield, visually impaired pedestrians cannot reliably tell whether vehicles have yielded in all lanes (4), or when crossable gaps are present because no vehicles are approaching (3). Accessible traffic signals would seem to be a logical alternative as these can reasonably be expected to (1) reliably stop most traffic and (2) provide notice to the pedestrian of when it is appropriate to cross.
The remainder of this report represents an attempt to integrate the above information. Recommendations are made for further research to support a rational approach to signalizing roundabouts where signals may provide needed pedestrian access.