Are “detectable warnings” (truncated domes) required for all curb ramps and, if so, what are the design requirements?
Currently, detectable warnings are not included in the MUTCD as a traffic control device. However, they are a requirement stemming from the Americans with Disabilities Act (ADA), to warn visually-disabled (blind or low-vision) pedestrians of the change from sidewalk to roadway as they leave the ramp to enter the crosswalk. On July 30, 2004, FHWA issued a memorandum reiterating that agencies must continue to comply with current ADA standards — including those for detectable warnings at curb ramps and blended transitions — when building new and altering existing pedestrian facilities. Further, the U.S. Access Board, part of the U.S. Department of Justice, the agency that administers the ADA, is planning to initiate a rulemaking process for adopting ADA Accessibility Guidelines for the Public Right-of-Way. The latest information on current and proposed design and placement requirements for detectable warnings may be viewed on the Access Board’s website at http://www.access-board.gov/ada
