4.7 Curb Ramps.
Curb ramps complying with 4.7 shall be provided wherever an accessible route crosses a curb.
Slopes of curb ramps shall comply with 4.8.2. The slope shall be measured as shown in. Transitions from ramps to walks, gutters, or streets shall be flush and free of abrupt changes. Maximum slopes of adjoining gutters, road surface immediately adjacent to the curb ramp, or accessible route shall not exceed 1:20.
The minimum width of a curb ramp shall be 36 in (915 mm), exclusive of flared sides.
Surfaces of curb ramps shall comply with 4.5.
4.7.5 Sides of Curb Ramps
If a curb ramp is located where pedestrians must walk across the ramp, or where it is not protected by handrails or guardrails, it shall have flared sides; the maximum slope of the flare shall be 1:10. Curb ramps with returned curbs may be used where pedestrians would not normally walk across the ramp.
4.7.7 Detectable Warnings
A curb ramp shall have a detectable warning complying with 4.29.2. The detectable warning shall extend the full width and depth of the curb ramp.
Curb ramps shall be located or protected to prevent their obstruction by parked vehicles.
4.7.10 Diagonal Curb Ramps
If diagonal (or corner type) curb ramps have returned curbs or other well-defined edges, such edges shall be parallel to the direction of pedestrian flow. The bottom of diagonal curb ramps shall have 48 in (1220 mm) minimum clear space as shown in figures here-under. If diagonal curb ramps are provided at marked crossings, the 48 in (1220 mm) clear space shall be within the markings . If diagonal curb ramps have flared sides, they shall also have at least a 24 in (610 mm) long segment of straight curb located on each side of the curb ramp and within the marked crossing.
Diagonal curb ramps are located at each corner of the intersection. There are flared sides on each diagonal curb ramp. The cross walks are placed so a minimum 48 inch (1220 mm) long clear space is provided at the bottom of the curb ramp inside the marked cross walk. An accessible route is provided across the island in the intersection.
Similar to precedent except that returned curb ramps are provided at each corner of the intersection. A minimum 48 inch (1220 mm) long clear floor space is provided at the bottom of the curb ramp within the marked crossing area. A well defined edge is provided at the side of each curb ramp.
Any raised islands in crossings shall be cut through level with the street or have curb ramps at both sides and a level area at least 48 in (1220 mm) long between the curb ramps in the part of the island intersected by the crossings.
Two flared-side curb ramps at each corner of the intersection. Each curb ramp is parallel to the direction of travel of pedestrians crossing the intersection. The curb ramps are in line with the marked crosswalk. An accessible route is provided through the island in the intersection.
Similar to precedent except the curb ramps do not extend the entire width of the cross walk. The curb ramp section and the side flares are located within the marked cross walk area on a segment of the straight curb.