Because this site gets a number of hits on accessibility specifications of actual curb cuts, I thought I would post a couple of resources for misguided visitors. Specifically I’ll outline the little that I’ve been able to find out about curb cuts and the Americans with Disabilities Act (ADA).
Definition
First off a definition from the Wikipedia entry on curb cuts:
A curb cut (US) or dropped kerb (UK) is a ramp leading smoothly down from a sidewalk to a street, rather than abruptly ending with a curb and dropping roughly 10–15 cm (4~6 inches).
Where
Page 4 of the official Checklist for Existing Facilities (PDF) from the US Department of Justice Americans with Disabilities Act Home Page asks the question, “Do curbs on the route have curb cuts at drives, parking and drop offs?” From this I’m going to posit that these are the three places where curb cuts are required.
Slope
The next paragraph in a discussion on ramps discusses the slope ration and states that “the slopes of ramps (be) no greater than 1:12,” it then goes on:
Slope is given as a ratio of the height to the length. 1:12 means for every 12 inches along the base of the ramp, the height increases one inch. For a 1:12 maximum slope, at at least one foot of ramp length is needed for each inch of height.
More Information
For those who are looking for more information, the US Department of Transportation Federal Highway Administration has a document entitled Designing Sidewalks and Trails for Access, including an entire chapter on “curb ramps” including information on how curb ramps impact different populations, different types, best practices and great diagrams.
If you’re looking for a basic checklist on facility accessibility, check out this Facilities Checklist from the National Center on Workforce and Disability.