ADA Truncated Domes come in many different sizes and colors as well as offering several different types of Materials composition. ADA Truncated Domes Material availability include Composite (Fiberglass), Cast Iron, Concrete, Granite and Stainless Steel. Concrete detectable warning panels come in typical sizes of 1’x1’ and 2’x 2’, And well as a range of thicknesses, from 1.5 inches to 4 inches thick...
The ADA Truncated Domes Federal Mandate was first instituted in 1991. At that time the mandate only required Transit companies, like subways, bus stops & other types of railway transportation, to comply. Compliance for all other wheel chair ramps, and areas without Tactile Warnings were exempt until 2001, when the mandate applied to ALL new wheel Chair ramp installations and areas with no Tactile (Curbs) warning, alerting the visually impaired that they were transitioning from a pedestrian safe zone, to a vehicular zone. (Tactiles Up to this point were typically the curb that is stepped off between vehicular areas & pedestrian.)
Without the curb warning in place, a visually impaired person would not know that they are passing from a safe Pedestrian area to a dangerous Vehicular area. Now with the domed warnings in place, and the agency for the visually impaired educating the people this was created for, a Clear warning, A DETECTABLE WARNING, is in place, and tragedies can be avoided.
The most familiar place (to the public) that these are found, is along the edges of railways. As noted above, Train stations, Subways and other rail forms of mass transit have been complying with this mandate since 2001. In addition to people encountering these Detectable Warning panels in these areas, they are often in the background of movie scenes. Once you read this, I am sure you will start to notice them everywhere you go, and in every movie that shows them.
Seeing that these Warnings are intended for the visually impaired, who can’t see colors, people have asked why the colors are important and have guideline requirements in the mandate. In the beginning the colors were mandated as a percentage of color difference between the Detectable Warning & the surface around it. Now they merely require light on dark, or vice versa. The domes can become a trip hazard for sighted people, so the color contrast alerts sighted people that the cast iron detectable warning - composite detectable warning - concrete detectable warning or any other type of Tactile warning being used, reducing their chances of tripping over them, from lack of vivid visual presence.
ALL IN ALL the detectable warning mandate protects the visually impaired, while still making sure not to cause and alternate problem for sighted people. Now that you know, look for these detectable warning panels along your travels. Look and try to figure out if they are a cast iron detectable warning - composite detectable warning - concrete detectable warning or any other type of Tactile warning.