“Under this regulation [DOJ implementing regulations for title II of the ADA], maintenance of pedestrian walkways by public entities is a covered program that is required to be made accessible by the installation of curb ramps where existing pedestrian routes cross curbs...”
--DOJ Title II Technical Assistance Manual

§35.151 New construction and alterations (a) Design and construction. Each facility or part of a facility constructed by, on behalf of, or for the use of a public entity shall be designed and constructed in such manner that the facility or part of the facility is readily accessible to and usable by individuals with disabilities, if the construction was commenced after January 26, 1992.

(b) Alteration. Each facility or part of a facility altered by, on behalf of, or for the use of a public entity in a manner that affects or could affect the usability of the facility or part of the facility shall, to the maximum extent feasible, be altered in such a manner that the altered portion of the facility is readily accessible to and usable by individuals with disabilities, if the alteration was commenced after January 26, 1992.

(c) Accessibility standards. Design, construction, or alteration of facilities in conformance with the Uniform Federal Accessibility Standards (UFAS) or with the Americans with Disabilities Act Accessibility Guidelines for Buildings and Facilities (ADAAG) shall be deemed to comply with the requirements of this section with respect to those facilities...Departures from particular requirements of either standard by the use of other methods shall be permitted when it is clearly evident that equivalent access to the facility or part of the facility is thereby provided.[...]

(e) Curb ramps.
(1) Newly constructed or altered streets, roads, and highways must contain curb ramps or other sloped areas at any intersection having curbs or other barriers to entry from a street level pedestrian walkway.
(2) Newly constructed or altered street level pedestrian walkways must contain curb ramps or other sloped areas at intersections to streets, roads, or highways.