Visual Detection of Detectable Warning Materials by Pedestrians with Visual Impairments - Final Report

2.3 Visual Detection

For each sidewalk type, Table 4 shows the percentage of participants who were able to see each detectable warning at 2.44 m (8 ft) and at 7.92 m (26 ft). Although most of the detectable warnings tested in this study were seen by most participants at a distance of 2.44 m (8 ft), a few combinations of sidewalk type and detectable warning color were not seen by many participants. At greater distance, up to 7.92 m (26 ft), certain combinations of detectable warning color and sidewalk were more likely to be seen than others.

Sidewalk color had an important influence on the number of participants who could see the single-color detectable warnings. Two-color (black-and-white) detectable warnings were seen by a high percentage of participants at all distances tested on all four sidewalk colors tested.