Dimensional Tolerances in Construction and for Surface Accessibility

1.1.12 Ramp cross slope. Measure for overall cross slope of ramps by establishing elevations at the extreme edges of the ramp at the top and bottom of the ramp and calculate the cross slope at these two locations using the horizontal ramp width and difference between elevations at the edges of the ramp (i.e. the rise over the run). A simple method of establishing the relative elevations of the top and bottom of each ramp is to use a rotating laser level on a tripod and document the difference in height on a stiff metal tape measure or surveyor's rod.

This method of establishing the running slope and cross slope is consistent with the requirements of ADA/ABA - AG, which gives the standard for running slope and cross slope as 1:12 and 1:48, respectively. Currently, these are the only ADA/ABA - AG requirements related to running and cross slope that must be met.