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

Perpendicular Curb Ramps (R304.2) (Section-by-Section Analysis)

Perpendicular curb ramps have a running slope that cuts through or is built up to the curb at right angles or meets the gutter grade break at right angles where the curb is curved. On corners with a large curb radius, it will be necessary to indent the gutter grade break on one side of the curb ramp in order for the curb ramp to meet the gutter grade break at right angles.

A turning space must be provided at the top of perpendicular 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 at the back of the sidewalk, 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 ramp run.

A minimum running slope of 5 percent and a maximum running slope of 8.3 percent are specified for perpendicular 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 top of the curb ramp. The running slope is measured parallel to the direction of pedestrian travel.

A maximum slope of 10 percent is specified for the flared sides of perpendicular curb ramps where a pedestrian circulation path crosses the curb ramp. The flared sides are part of the pedestrian circulation path, but are not part of the pedestrian access route. The slope of the flared sides is measured parallel to the curb line. The 10 percent maximum slope for the flared sides is the same as in the 2004 ADA and ABA Accessibility Guidelines (see 403.6). Transportation officials have reported that the 10 percent maximum slope for the flared sides can make it difficult to provide two perpendicular curb ramps at some street corners due to the width of the flared sides at the base of the curb ramp. The Access Board is considering increasing the maximum slope for the flared sides to 12.5 percent or 16.7 percent to address this issue.

Question 18. Comments are requested on whether the maximum slope for the flared sides of perpendicular curb ramps should be increased from 10 percent to 12.5 percent or 16.7 percent, and what impact such a change would have on providing two perpendicular curb ramps at street corners. Comments are also requested on any public safety issues that may arise from increasing the maximum slope for the flared sides from 10 percent to 12.5 percent or 16.7 percent.