Guide to the ADA Standards

Diagonal Curb Ramps [§406.6]

If curb ramps are placed diagonally at an intersection, it is important that clear space 48” long min. is available at the bottom that is outside active vehicle traffic lanes and is located within marked crossings, where provided. A segment of curb at least 24” long beyond flares must be provided on both sides of curb ramps with side flares within marked crossings. This curb segment provides an orienting cue at crossings for people with vision impairments.

Recommendations: Perpendicular curb ramps are preferred over diagonal curb ramps. Unless the radius is large enough, it can be difficult to locate the clear space at the bottom of diagonal curb ramps that is outside active traffic lanes. The orientation also can mislead people with vision impairments who use curb slopes as a cue to crossings.