For the cues evaluated in our study, the participants' performance was the best in the two conditions involving underfoot bars mounted perpendicular to the desired walking direction, intermediate for underfoot bars and a simulated curb oriented parallel to the desired direction of travel, and the worst for tactile arrows and the running slope of a
curb ramp. Better performance might have been observed had the participants received more instruction and practice and been required to use a strategy from which it was possible to obtain good directional information.
It is easy to violate
curb ramp requirements because there are many components to address, including how a
curb ramp meets the adjacent sidewalk, curb and street For example, the bottom of a
curb ramp often meets a gutter; the flares of a flared-type
curb ramp meet a curb; and the top of the
curb ramp meets the route that continues through the site.
"Our solution is to train engineers in the department on
curb ramp design, including the appropriate use of truncated domes."
The ADA provides strict guidelines on how to construct
curb ramps, recommending slopes of a certain degree, how tall the truncated domes must be, the spacing of the domes and other design specifications - down to the allowable millimeter.
* Counter slopes of adjoining gutters and road surfaces immediately adjacent to the
curb ramp not be steeper than 1:20
The Access Board has issued a 4-page list of resources for
curb ramp materials and surfaces.
* If a
curb ramp is located where pedestrians must walk across it or where it is not protected by handrails or a guardrail, it shall have flared sides with a minimum slope of 1:10 (1" vertical rise in a 10" horizontal length).
In a landmark decision, the United States District Court has mandated that the City of Philadelphia install
curb ramps on all streets in which contracts for street resurfacing were let for bid after January 26, 1992.