ADAAG Manual

Detectable Warnings [4.7.7]

The edges of curbs can provide a cue to people with vision impairments. Since curb ramps remove this detectable drop-off, ADAAG originally required a distinctive dome patterning for the surface of curb ramps detectable by canes or by foot so that people with vision impairments could detect the transition from pedestrian area to street. In response to business and user concerns about the need and specifications for this detectable warning, this requirement was suspended in 1994 pending further study. Alternative means of providing a tactile warning at curb ramps that empty into streets may be acceptable (though not required) until a requirement may be established. Jurisdictions may continue to install the truncated domes specified in ADAAG or other surfaces or technologies if they wish but are not obligated to do so.