UPDATE: The 2010 Standards do not require detectable warnings on curb ramps.
The 2010 Standards apply to detectable warnings on developed sites. They do not apply to the public right-of-way. Scoping for detectable warnings at all locations other than transit platform edges has been eliminated from the 2010 Standards. However, because detectable warnings have been shown to significantly benefit individuals with disabilities at transit platform edges, the 2010 Standards provide scoping and technical requirements for detectable warnings at transit platform edges.
You may have been having problems finding the requirement for detectable warnings on curb ramps in the revised ADA/ABA Guidelines (published July 23, 2004). You won’t find it here.
But you can find it in the March 23, 2007 supplement at this link: Modification to 406 of Appendix D
406.8 Detectable Warnings. A curb ramp shall have a detectable warning complying with 705. The detectable warning shall extend the full width of the curb ramp (exclusive of flared sides) and shall extend either the full depth of the curb ramp or 24 inches (610 mm) deep minimum measured from the back of the curb on the ramp surface.
Another source of confusion I have found, in regards to the detectable paver rules, is the color contrast requirements. Do the pavers need to contrast with the ramp, the right-of-way, or both?
While your information is technically correct in that the ADA does not require detectable warnings anywhere other than transit platforms these guidelines only apply to devloped sites-not the public right-of-way.
“The 2010 Standards apply to detectable warnings on developed sites. They do not apply to the public right-of-way.”
The requirements for the public right-of-way are set by the US Access Board. The US Access Board published draft guidelines in July 2011. These draft guidelines actually expand the use of detectable warnings in curb ramps.
Here is the section from the proposed ROW guidelines:
R208 Detectable Warning Surfaces
R208.1 Where Required. Detectable warning surfaces complying with R305 shall be provided at the following locations on pedestrian access routes and at transit stops:
Curb ramps and blended transitions at pedestrian street crossings;
Pedestrian refuge islands;
Pedestrian at-grade rail crossings not located within a street or highway;
Boarding platforms at transit stops for buses and rail vehicles where the edges of the boarding platform are not protected by screens or guards; and
Boarding and alighting areas at sidewalk or street level transit stops for rail vehicles where the side of the boarding and alighting areas facing the rail vehicles is not protected by screens or guards.