36 CFR Parts 1190 and 1191 ADA and ABA Accessibility Guidelines - Preamble (Discussion of Comments and Changes)
Section 402 lists the various elements that can be part of an accessible route: walking surfaces, doorways, ramps, elevators, and platform lifts. Walking surfaces must have a running slope of 1:20 or less. Those portions of accessible routes that slope more than 1:20 must be treated as ramps or curb ramps.
Comment. Comments noted that curb ramps should be included in the list of accessible route components.
Response. A reference to curb ramps has been added to this list in the final rule (402.2). In addition, the Board has clarified that only the run of curb ramps, not the flared sides, can be considered part of an accessible route.