Detectability and Traversability of Detectable Warning Surfaces
Joseph Alderson
School of Engineering
Faculty Supervisor: Yiyi Wang
Before curb ramps were widely installed, pedestrians with low vision could detect the boundary between the sidewalk and the street by feeling the curb drop-off with their cane or feet. The introduction of curb ramps removed this vital cue, increasing the risk of visually impaired pedestrians unintentionally entering the roadway. To address this, the Americans with Disabilities Act (ADA) through the Standards for Accessible Design require truncated dome detectable warning surfaces at the base of all curb ramps. While these warning surfaces greatly improve safety for pedestrians with low vision, many mobility-impaired users find them difficult to traverse and report dissatisfaction with the design.
In the late 1980s and 1990s, researchers tested variations in dome size, spacing, materials, and color, as well as other commercially available detectable surfaces. Their studies concluded that truncated domes were the most detectable option while posing relatively minimal mobility challenges. However, this research was limited: it did not explore novel geometric patterns beyond domes or bars, nor did it implement rigorous methods for evaluating navigability. This project seeks to address those gaps by investigating new, non-commercially available detectable surface geometries and by applying modern techniques to quantitatively measure traversability. The ultimate goal is to develop a detectable surface that provides detection equal to or better than truncated domes while offering improved accessibility for mobility-impaired users.