36 CFR Part 1190, Proposed Accessibility Guidelines for Pedestrian Facilities in the Public Right-of-Way: Notice of Proposed Rulemaking (NPRM)

Parallel Curb Ramps (R304.3) (Section-by-Section Analysis)

Parallel curb ramps have a running slope that is in-line with the direction of sidewalk travel and lower the sidewalk to a level turning space where a turn is made to enter the pedestrian street crossing.

A turning space must be provided at the bottom of parallel curb ramps. The turning space must be 1.2 meters (4 feet) minimum by 1.2 meters (4 feet) minimum, and is permitted to overlap other turning spaces and clear spaces. Where the turning space is constrained on two or more sides, the turning space must be 1.2 meters (4 feet) minimum by 1.5 meters (5 feet) minimum, with the 1.5 meters (5 feet) dimension provided in the direction of the pedestrian street crossing.

A minimum running slope of 5 percent and a maximum running slope of 8.3 percent are specified for parallel curb ramps, and the ramp length is limited to 4.5 meters (15 feet). A maximum running slope of 2 percent is specified for the turning space at the bottom of the curb ramp. The running slope is measured parallel to the direction of pedestrian travel.