49 CFR Parts 37 & 38 - Department of Transportation (DOT) ADA Regulations

406.8--Modification to 406 of Appendix D to 36 CFR Part 1191

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.