Tactile paving (also called truncated domes, detectable warnings, Tactile Ground Surface Indicators, detectable warning surfaces) is a system of textured ground surface indicators found on many footpaths, stairs and train station platforms to assist blind and vision impaired pedestrians.
Tactile warnings provide a distinctive surface pattern of "truncated domes" or cones (which are small domes or cones that have had their tops cut off, or truncated) or "truncated bars" detectable by long cane or underfoot which are used to alert people with vision impairments of their approach to streets and hazardous drop-offs. People who are blind or visually impaired are alerted of impending danger from vehicle impact or a grade change. There is a disagreement in the design community and the community of users if the interior use of these bars represents a tripping hazard.
Originally instituted at crosswalks and other hazardous vehicular ways by countries like Japan, the United Kingdom and Australia, among others, the United States picked up the standard in the early 1990s, after passage of the Americans with Disabilities Act (ADA). Canada started incorporating the use in transportation first in the 1990s then added them to the built environment in the early 2000s.
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