36 CFR Parts 1190 and 1191 ADA and ABA Accessibility Guidelines - Preamble (Discussion of Comments and Changes)

Comment. Section 406.6 provides specifications for diagonal (or corner type) curb ramps. These curb ramps must have a 48 inch minimum clear space at the bottom. Comments advised that this space should be provided outside active traffic lanes of the roadway so that persons traversing the ramp are not in the way of oncoming traffic from either direction at an intersection.

Response. Clarification has been added in the final rule that the clear space at the bottom of diagonal curb ramps must be located "outside active traffic lanes of the roadway."

Comment. Requirements for diagonal curb ramps in section 406.6 also specify that a segment of straight curb at least 2 feet long must be provided on each side of the curb ramp and within the marked crossing. This portion of curb face provides a detectable cue to people with vision impairments traveling within the crosswalk. Comments noted that this segment of curb does not have to be horizontally straight to provide such a cue and that achieving straight segments two feet long within marked crossings is very difficult under standard intersection design conventions.

Response. The requirement in section 406.6 that the 2 foot curb segment aside diagonal curb ramps be "straight" has been removed. The segment can be provided at arced portions of the curb, but must still be located within marked crossings.