Pedestrians who are blind use audible and tactile cues in independent travel. At intersections with fixed-time signal phasing and consistent traffic flow, traffic light changes will be reflected in parallel or perpendicular traffic surges. The sounds of these surges are used by blind pedestrians to identify appropriate crossing intervals. Intersections that have actuated signal timings, complex traffic patterns, or intermittent or sporadic traffic volumes may pose problems for pedestrians who have vision impairments. At these intersections, the signals for automobile and pedestrian traffic do not automatically correspond. Frequently, a separate WALK signal and phase is provided for pedestrians in response to a pushbutton. At this type of crossing (as well as at several other types, including midblock crossings where there is no parallel flow to rely on), an accessible pedestrian signal (APS) may be desirable to provide blind and low-vision pedestrians with an equivalent to the visual signal provided for other pedestrians.
