The federal Department of Transportation (DOT) has adopted the transit stops and transit shelters portion of PROWAG, effective January 17, 2025. This means that all new or altered transit stops must be compliant, for all transit agencies. Many existing transit stops do not meet the requirements, particularly with maneuvering space for wheelchairs. Presumably the regional transit agencies will be modifying their transit stop and transit shelter designs to be compliant. Often providing sufficient space requires the transit agency and transportation agency to either use existing right-of-way that is not reflected by the current sidewalk edge (which is often true), or to negotiate easements or purchase with private property owners. The regulations does not just apply to transit agencies, it applies to all public agencies including the transportation agencies.
The language from PROWAG is below.
R309 Transit Stops and Transit Shelters
R309.1 Transit Stops
Transit stops shall comply with R309.1.
R309.1.1 Boarding and Alighting Areas
Boarding and alighting areas at sidewalk or street-level transit stops must serve each accessible vehicle entry and exit and shall comply with R309.1.1 and R309.1.3.
R309.1.1.1 Dimensions
Boarding and alighting areas shall have a clear length of 96 inches (2440 mm) minimum, measured perpendicular to the face of the curb or street edge, and a clear width of 60 inches (1525 mm) minimum, measured parallel to the street.

R309.1.1.2 Slope
The slope of boarding and alighting areas measured parallel to the street shall be the same as the grade of the street. The slope of boarding and alighting areas measured perpendicular to the streetshall be 1:48 (2.1%) maximum.
R309.1.2 Boarding Platforms
Boarding platforms at transit stops shall comply with R309.1.2 and R309.1.3.
R309.1.2.1 Platform and Vehicle Floor Coordination
Boarding platforms shall be positioned to coordinate with vehicles in accordance with the applicable requirements in 49 CFR parts 37 and 38.
The slope of the boarding platform measured parallel to the track or street shall be the same as the grade of the track or street. The slope of the boarding platform measured perpendicular to the track or street shall be 1:48 (2.1%) maximum.
R309.1.3 Common Requirements
Boarding and alighting areas and boarding platforms shall comply with R309.1.3.
R309.1.3.1 Surfaces
The surfaces of boarding and alighting areas and boarding platforms shall comply with R302.6.
R309.1.3.2 Connection to Existing Pedestrian Circulation Paths
In alterations, boarding and alighting areas and boarding platforms shall be connected to existing pedestrian circulation paths by pedestrian access routes complying with R302.
R309.2 Transit Shelters
Transit shelters shall comply with R309.2.
R309.2.1 Connection to Boarding and Alighting Areas
Transit shelters shall be connected by pedestrian access routes complying with R302 to boarding and alighting areas complying with R309.1.1 or boarding platforms complying with R309.1.2.

Transit shelters shall provide a minimum clear space complying with R404 entirely within the shelter. Where seating is provided within transit shelters, the clear space shall be located either at one end of a seat or so as to not overlap the area within 18 inches (455 mm) from the front edge of the seat.
R309.2.3 Environmental Controls
Where provided, environmental controls within transit shelters shall be proximity-actuated.
Protruding objects within transit shelters shall comply with R402.