To quote the TDLR Technical Memorandum 08-01, “With the intention of harmonizing both State and Federal requirements, the Department issues the following technical clarifications regarding surface texture requirements at curb ramps.”
TM 08-01 then goes on to confuse the issue further by treating differently curb ramps within the public ROW (right of way) and those that are not within the ROW.
From the Texas Accessibility Standards (italics denote a change from the ADAAG):
(1) Textures shall consist of exposed crushed stone aggregate, roughened concrete, rubber, raised abrasive strips, or grooves extending the full width and depth of the curb ramp. Surfaces that are raised, etched, or grooved in a way that would allow water to accumulate are prohibited.
(2) For purposes of warning, the full width and depth of curb ramps shall have a light reflective value and texture that significantly contrasts with that of adjoining pedestrian routes.
Per TM 08-01, section 4.7.4(1) & (2) do not apply to curb ramps within the public ROW. Instead, these curb ramps shall have detectable warnings that comply with section 4.29.2:
4.29.2* Detectable Warnings on Walking Surfaces. Detectable warnings shall consist of raised truncated domes with a diameter of nominal 0.9 in (23 mm), a height of nominal 0.2 in (5 mm) and a center-to-center spacing of nominal 2.35 in (60 mm) and shall contrast visually with adjoining surfaces, either light-on-dark, or dark-on-light.
The material used to provide contrast shall be an integral part of the walking surface. Detectable warnings used on interior surfaces shall differ from adjoining walking surfaces in resiliency or sound-on-cane contact.
The ADAAG(1991) and the revised ADA/ABA Guidelines(2004), do not specify contrast for curb ramps. The contrast is a requirement for the detectable warnings which are required to be provided on curb ramps.
There is no conflict for curb ramps within the ROW; the contrast is only required on the detectable warnings. The remainder of the curb ramp may be plain concrete.
If a curb ramp is not located within the ROW, section 4.7.4(2) still applies; the full width and depth of the curb ramp shall contrast with adjoining pedestrian routes even if detectable warnings are not used.
Don’t try too hard to understand it. This story is not over.