ADA Detectable Warnings

History

• ADA detectable warnings were a part of the American with Disabilities Act when it was first passed in 1990. Their requirements were temporarily suspended from 1994 to 2001 when concerns were raised about their specifications, availability of complying products and maintenance issues. The suspension applied to all detectable warnings except for boarding platforms at transit stations. The suspension was lifted on July 26, 2001; ADA detectable warnings were once again a requirement that engineers, architects, designers, and contractors had to adhere with to be in compliance with the ADA law.

Description

• The warnings are domes that are .9 inches in diameter and .2 inches in height. They are placed in a pattern that has a center-to-center spacing of 2.35 inches. Detectable warnings can be made of plastic, concrete, tiles or metal. They are of contrasting color to the surrounding surface. The detectable warnings are an integral part of the walking surface. ADA detectable warnings are required to extend 24 inches into the path of travel and along the entire length of the pathway.

Location

• ADA detectable warnings are required to be placed in all locations where a person may enter a street or vehicle pathway. ADA detectable warnings are typically seen at corners of sidewalks and at loading zones or drop-off locations. They are placed in these pathways to alert a person with vision impairments that a street or vehicle pathway is on the other side of the detectable warning. They can also be seen at shopping centers to alert the shoppers where the parking lot starts.

Ramps

• The warnings are required at curb ramps placed at street corners. They are also required at accessible loading and drop-off zones where the sidewalk curb then ramps down to the street to allow for a wheelchair to enter. When placed at a corner location, the domes of the warnings shall be placed perpendicular or radial to the grade break between the ramp and the street at a minimum of 4 feet in width for each sidewalk the detectable warning meets.