R304 — Curb Ramps and Blended Transitions

R304.1 General. Curb ramps and blended transitions shall comply with R304 and have detectable warning surfaces in accordance with R205. R304.2 Perpendicular Curb Ramps. Perpendicular curb ramps shall comply with R304.2 and R304.5. R304.2.1 Running Slope. The running slope of a curb ramp shall be perpendicular to the curb or gutter grade break. The running slope of the curb ramp shall be 1:12 (8.3%) maximum. Exception: Where the curb ramp length must exceed 15 feet (4.6 m) to achieve a 1:12 (8.3%) running slope, the curb ramp length shall extend at least 15 feet (4.6 m) and may have a running slope greater than 1:12 (8.3%). R304.2.2 Cross Slope. The cross slope of a curb ramp run shall be 1:48 (2.1) maximum. Exception: At crosswalks, the cross slope of the curb ramp run shall be permitted to be equal to or less than the cross slope of the crosswalk as specified by R302.5. R304.2.3 Grade Breaks. Grade breaks at the top and bottom of a curb ramp run shall be perpendicular to the direction of the curb ramp run. Grade breaks shall not be permitted on the surfaces of curb ramp runs and landings. Surface slopes that meet at grade breaks shall be flush. R304.2.4 Clear Area. A clear area 48 inches (1220 mm) wide minimum by 48 inches long (1220 mm) minimum shall be provided beyond the bottom grade break of the perpendicular curb ramp run and within the width of the crosswalk. At shared use paths, the clear area shall be as wide as the shared use path. The clear area shall be located wholly outside the vehicle travel lanes, including bicycle lanes, that run parallel to the crosswalk. The running slope of the clear area shall be 1:20 (5.0%) maximum. The cross slope of the clear area shall be as specified by R302.5. R304.2.5 Landing. When a change in direction is necessary to access a curb ramp from a pedestrian access route, a landing shall be provided at the top of the curb ramp. The landing shall be 48 inches (1220 mm) wide minimum by 48 inches (1220 mm) long minimum. At shared use paths, the landing shall be as wide as the shared use path. Where a landing serves only one curb ramp, the landing slope measured perpendicular to the curb ramp run shall be equal to or less than the cross slope of the curb ramp run, and the landing slope measured parallel to the curb ramp run shall be 1:48 (2.1%) maximum. Where a landing serves two curb ramps, the landing slope in either direction of travel shall not exceed the cross slope of the crosswalk parallel to the direction of travel as specified by R302.5. R304.2.6 Side Treatments. Where a pedestrian circulation path crosses the side of a curb ramp, the side of the curb ramp shall be flared. The slope of the flared side shall be 1:10 (10.0%) maximum, measured parallel to the adjacent curb line. R304.2.7 Connection to Pedestrian Facilities. Perpendicular curb ramps or their landings shall be connected to adjacent pedestrian facilities by pedestrian access routes complying with R302. A transitional segment may be used in the connection. R304.3 Parallel Curb Ramps. Parallel curb ramps shall comply with R304.3 and R304.5. R304.3.1 Running Slope. The running slope of the curb ramp run shall be parallel to the curb and shall be 1:12 (8.3%) maximum. Exception: Where the curb ramp run length must exceed 15 feet (4.6 m) to achieve a 1:12 (8.3%) running slope, the curb ramp run length shall extend at least 15 feet (4.6 m) and may have a running slope greater than 1:12 (8.3%). R304.3.2 Cross Slope. The cross slope of the curb ramp run shall be 1:48 (2.1%) maximum. R304.3.3 Grade Breaks. Grade breaks at the top and bottom of a curb ramp run shall be perpendicular to the direction of the curb ramp run. Grade breaks shall not be permitted on the surfaces of curb ramp runs or landings. Surface slopes that meet at grade breaks shall be flush. R304.3.4 Landings. Landings shall be provided at the bottom of parallel curb ramps. Landings shall be 48 inches (1220 mm) wide minimum by 48 inches (1220 mm) long minimum. The slope of the landing, measured parallel to the direction of travel on the curb ramp run, shall be permitted to be equal to or less than the slope of the roadway or the cross slope of the crosswalk as specified by R302.5. The cross slope of the landing shall be 1:48 (2.1%) maximum measured perpendicular to the direction of travel on the curb ramp run. R304.4 Blended Transitions. Blended transitions shall comply with R304.4 and R304.5. R304.4.1 Running Slope. The running slope of blended transitions shall be 1:20 (5.0%) maximum. R304.4.2 Cross Slope. The cross slope of blended transitions shall be equal to or less than the cross slope of the crosswalk as specified by R302.5. R304.4.3 Bypass. Where a blended transition serving more than one pedestrian circulation path has a running slope greater than 1:48 (2.1%), a pedestrian access route shall be provided so that a pedestrian not crossing the street may bypass the blended transition. R304.5 Common Requirements. Curb ramps and blended transitions shall comply with R304.5. R304.5.1 Width. The width of curb ramp runs (excluding any flared sides) and blended transitions shall comply with R304.5.1.1 or R304.5.1.2, as applicable. R304.5.1.1 Curb Ramps and Blended Transitions Not on Shared Use Paths. The clear width of curb ramp runs (excluding any flared sides) and blended transitions not on shared use paths shall be 48 inches (1220 mm) minimum. R304.5.1.2 Curb Ramps and Blended Transitions on Shared Use Paths. On shared use paths, the width of curb ramp runs (excluding any flared sides) and blended transitions shall be equal to the width of the shared use path. R304.5.2 Change of Grade. At gutters and streets where a change of grade occurs adjacent to curb ramps and blended transitions, the change of grade shall comply with the requirements contained in (A) or (B) below: A. The change of grade shall not exceed 13.3 percent, or B. A transitional space shall be provided at the bottom of the running slope of the curb ramp run or blended transition. The transitional space shall extend 24 inches (610 mm) minimum in the direction of pedestrian travel and the full width of the curb ramp run or blended transition. Transitional spaces shall have running slopes of 1:48 (2.1%) maximum and cross slopes no greater than the cross slope of the crosswalk as specified by R302.5. R304.5.3 Crosswalks. Perpendicular curb ramp runs, parallel curb ramp landings, and 48 inches (1220 mm) minimum width of blended transitions, except those at shared use paths, shall be contained wholly within the width of the crosswalks they serve. At shared use paths, the full width of a perpendicular curb ramp run, parallel curb ramp landing, or the blended transition shall be contained wholly within the width of the crosswalk it serves. R304.5.4 Surfaces. Surfaces of curb ramps and blended transitions shall comply with R302.6 except that changes in level are not permitted.