Designs that provide universal accessibility at stops and stations not only increase the equity of transit systems, but also reduce operational costs.
Making fixed route transit service simpler, more comfortable, and more convenient for passengers using mobility devices can reduce the need for costly paratransit trips, reduce dwell time at stops, and, by substituting for ramp or lift deployment, eliminate or reduce the use of one of the most expensive subsystems on a transit vehicle.
Sidewalks & Crossings
1For pedestrian travel paths, a clear width of 8–12 feet is preferred where transit is present, and may be wider based on pedestrian and transit rider capacity. Pinchpoints less than 6 feet wide create capacity and comfort issues and should be avoided.
A 4-foot clear width is acceptable around some design elements like shelters and seating,1 and may be used especially where access is helpful but not essential, such as between a curb and the back of a building-facing shelter. Shelters and seating should be positioned so that all riders can comfortably wait, board, and alight without obstruction (see Small Transit Shelter).
2Turns in travel paths must have a landing at least 4 feet deep (ADAAG §403), and a minimum 4-foot by 5-foot turning space is preferred (PROWAG §304.2.1).
3Crosswalks must be accessible, with special attention to both people using wheelchairs and wheeled mobility devices and people with no or low vision. Curb ramps must be provided at all street crossings that involve a change in grade. Do not obstruct the top of the curb ramp.2
Curb ramps and other travel paths should be designed to prevent the accumulation of water and snow. Ramps may not have a slope exceeding 1:12. Ramps must have a landing for each 30 inches of rise (ADAAG §405).
Inclines and cross slopes of the street may impact other surfaces and should be accounted for in curb heights, sidewalks and boarding platforms, and drainage infrastructure. A 1 to 2% slope is often needed for proper drainage of sidewalks.
Transit Platforms
4An accessible boarding area must be provided, typically measuring 5 feet long (parallel to the curb) by 8 feet wide (perpendicular to the curb). This includes 5 feet of width for a wheelchair waiting area, plus additional width to deploy a wheelchair ramp to serve the waiting area (typically 3 feet). Longer ramps may require additional length (see ADAAG §810.2.2).
To provide accessible boarding, the vertical step between a platform and a vehicle (or ramp) must not exceed 5/8 inch, with a maximum horizontal gap of 3 inches (49 CFR §38.23) (see Transit Curbs).
For near-level boarding, bridge plates used to enable accessible boarding should not rise more than 3 inches or exceed 1:8 slope, with shallower slopes preferred. The slope for a bridge plate depends on the height of the vehicle floor and ranges from 1:4 to 1:12 [49 CFR §38.83(c)(5)].
Transit platform surfaces, like sidewalks, must meet specific slope requirements. Cross slopes on most sidewalks should be between 0.5% and 2% to achieve both good drainage and accessibility. Landing areas should have less than 1% cross slope to facilitate the accessible boarding area (ADAAG §403).
Travel paths and ramps must comply with other accessibility requirements (see ADA Std. Chapter 4: Accessible Routes and PROWAG Ch. R3: Technical Requirements for additional regulations and guidance).
Dan Tutt
- An absolute minimum 3 feet of clear continuous width must be provided per ADA Accessibility Guidance, though proposed US guidance suggests a 4-feet minimum continuous width.
“403 Accessible Routes.” 2010 ADA Standards for Accessible Design. US Access Board, United States Department of Justice, Washington, DC: 2010.
“R302.4, Technical Requirements.” Proposed Accessibility Guidelines for Pedestrian Facilities in the Public Right-of-Way. US Access Board, Washington, DC: 2011. ↩︎ - 36-inches is the absolute minimum required by ADA Standards (ADAAG §403), though a 48-inch minimum is proposed by PROWAG guidance (§R304.2).
“403 Accessible Routes.” 2010 ADA Standards for Accessible Design. US Access Board, United States Department of Justice, Washington, DC: 2010.
“R304.2, Technical Requirements.” Proposed Accessibility Guidelines for Pedestrian Facilities in the Public Right-of-Way. US Access Board, Washington, DC: 2011. ↩︎