In Detroit, a curb ramp is located too far from the corner, and a nearby tree on the west side of the intersection can obstruct drivers who don't expect to encounter a pedestrian crossing. Photo: H.R. Gray

The United States Access Board, a federal agency that develops design criteria to accommodate people with disabilities, operates a Web site ( that provides detailed information on complying with ADA guidelines. Check it if you're unsure what complies with the law before starting any work. The board also provides free online training and referrals to consultants who specialize in disability-related design at the standard rates for professional services ($150 to $300/hour). Others charge a specific rate for each student attending a class, such as $500 to $750/student, with a minimum class size required. The final cost of custom-designed courses is negotiable.

Although it costs more up front, advance consulting can save money in the long run.

One Midwestern city found this out the hard way after signing a settlement agreement with a local disability-rights group.

After agreeing on a design to make all 1,000 curb ramps ADA-compliant, public works proceeded to build them over the next year. Three-quarters of the way through the project, the advocacy group notified the department that 70% were installed incorrectly.

When the department hired us to inspect and measure the ramps, we found more than 75% failed to meet guidelines. The city spent more than $1.5 million on replacement. In residential areas curb ramps average $1,700 to 2,000 each; at intersections with traffic lights and other signaling devices a curb ramp can exceed $4,000 — or $32,000/intersection.

Although the city's intentions were good, training beforehand and a conversation with an experienced consultant would have prevented the errors. Even working with the advocacy group early on would have prevented the incorrect curb ramps from proceeding as far as they did.

— Robert Scott is vice president of construction management consulting firm H.R. Gray. He may be contacted at

Editor's note: Next month, learn about the importance of ADA compliance from a user's perspective.