Detectable warnings, a distinctive surface pattern of domes detectable by cane or underfoot, are used to alert people with vision impairments of their approach to streets and hazardous drop-offs. The ADA Accessibility Guidelines (ADAAG) require these warnings on the surface of curb ramps, which remove a tactile cue otherwise provided by curb faces, and at other areas where pedestrian ways blend with vehicular ways. They are also required along the edges of boarding platforms in transit facilities and the perimeter of reflecting pools.
Suspension of Requirements (1994 - 2001)
The Board temporarily suspended the requirements for
detectable warnings in 1994 due to concerns raised about the specifications, the
availability of complying products, maintenance issues such as snow and ice
removal, usefulness, and safety. This suspension applied to all requirements for
detectable warnings except those at boarding platforms in transit stations. The
departments of Justice (DOJ) and Transportation (DOT), which maintain
enforceable standards based on ADAAG, joined the Board in this action. As a
result, the requirements for detectable warnings were temporarily removed from
the ADA standards. The suspension expired on July 26, 2001. Consequently, the
requirements for detectable warnings at curb ramps and other areas are again
part of ADAAG and the enforceable standards. Questions regarding the
enforceability of these requirements should be directed to DOJ or DOT.
Update of the ADA Accessibility Guidelines
During the suspension, the Board sponsored further
research on detectable warnings. The Board also conducted a comprehensive review
of ADAAG in an effort to update its requirements. In addition, it resumed work
on developing a supplement to ADAAG specific to public rights-of-ways. Because
issues concerning the use of detectable warnings are most relevant to public
streets and sidewalks, the Board determined that provisions for detectable
warnings on curb ramps should be addressed in rulemaking on public
rights-of-ways rather than facilities on sites. As a result, the Board did not
include requirements for detectable warnings at curb ramps (or hazardous
vehicular areas and reflecting pools) in its proposal to update ADAAG.
Rulemaking on Public Rights-of-Ways
Currently, the Board is in the process of developing
guidelines on public rights-of-ways that, once finalized, will supplement the
new ADAAG. While ADAAG covers various features common to public streets and
sidewalks, such as curb ramps and crosswalks, further guidance is necessary to
address conditions unique to public rights-of-way. Constraints posed by space
limitations at sidewalks, roadway design practices, slope, and terrain raise
valid questions on how and to what extent access can be achieved. Guidance on
providing access for blind pedestrians at street crossings is also considered
essential.
In June 2002, the Board released guidelines on public rights-of-way in draft form and made them available for public comment. Through this release, the Board sought information and feedback, including usability and cost data, for its use in developing a proposed rule, which will provide an additional opportunity for comment in the future. The Board released a revised draft in November 2005 based on the comments received. The guidelines are based on recommendations the Board received from an advisory body it had chartered, the Public Rights-of-Way Access Advisory Committee. This committee included representation from disability organizations, public works departments, transportation and traffic engineering groups, design professionals and civil engineers, government agencies, and standards-setting bodies. The committee’s recommendations, which are contained in a report, "Building a True Community," include new specifications for detectable warnings.
The draft guidelines, consistent with the advisory committee’s recommendations, would revise the technical criteria. The revised specifications are responsive to concerns that had been raised about the impact of the truncated dome surface on wheelchair maneuvering. The Board believes that the draft revised specifications, which permit wider dome spacing, an in-line grid pattern, and smaller surface coverage at curb ramps (24 inches instead of the full ramp length, set back from the curbline) will improve usability of surfaces without affecting detectability.
Additional rulemaking steps, including another public comment period, must be completed before the Board can finalize the rights-of-way guidelines. At this time, the original detectable warning specifications in the current ADAAG remain in effect. However, ADAAG does include an “equivalent facilitation” clause (section 2.2) which permits departures from the guidelines that provide equal or greater access. The Board believes that the specifications for detectable warnings in the draft rights-of-way guidelines provide a level of access substantially equal to or greater than that currently specified by ADAAG. However, the Board does not have the statutory authority to officially make such a determination. This authority resides with the DOT and DOJ, the agencies which enforce the design requirements of the ADA. DOT, which also enforces certain ADA provisions concerning access for pedestrians, has issued guidance consistent with the Board's position.