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

2.12 Comments from Participants

The experimenters did not solicit opinions or comments from participants regarding the detectable warnings outside of the data collection protocol. However, experimenters recorded comments whenever they were offered. Some participants commented frequently while others did not comment at all, so these comments should be considered individual opinions rather than group consensus. The complete list of comments is presented in Appendix G and major findings are summarized below.

The black-and-white stripes and the federal yellow detectable warnings received the most favorable comments. The black-and-white stripe detectable warning was often called “very attention-getting” and some participants called it their favorite detectable warning, but a few others noted that the pattern appears to have depth or looks like a metal grate. Some noted that the black stripes “disappear” when placed on the asphalt sidewalk. Many participants said that the federal yellow detectable warning was very likely to get their attention, but a few others were concerned that the contrast was insufficient on the white concrete sidewalk.

Some participants noted concerns about detectable warnings that might not be recognized as warnings or that might be mistaken for other things. Dark detectable warnings such as black, dark gray, and black with white border were sometimes thought to look like holes, asphalt patches, or shadows on the sidewalk. The light gray, dark gray, and white concrete detectable warnings were sometimes thought to look like concrete patches. The brown concrete and orange-red detectable warnings were some times thought to look like cardboard or rust.

The black-and-white patterned detectable warnings received mixed feedback on the white concrete sidewalk and the asphalt sidewalk. Although the internal contrast of these detectable warnings was typically sufficient to provide high visibility, some participants commented that the white sections of the detectable warnings blend into the white concrete sidewalk or did not help them to see the detectable warning. The same was said about the black sections of the detectable warnings on the asphalt sidewalk. These sentiments were most frequent with regard to detectable warnings whose borders were similar in reflectance to the sidewalk (e.g., white border/white concrete sidewalk; black border/black asphalt sidewalk). The black–and-white stripe pattern sometimes looked like a metal grate to two participants.