Building codes for handicapped ramps are found in 36 CFR part 1191 Appendices B and D, also known as the 2004 Americans With Disabilities Act Accessibility Guide. Additional requirements for governmental facilities are found in 28 CFR 35.151 and, for commercial facilities, in 28 CFR part 36 subpart D.
The code requirements for ramps on accessible routes and for curb ramps are published in Chapters 405 and 406, respectively, of the 2004 Accessibility Guide. The guide defines the maximum allowable running slope and cross slope for ramps of various sizes. Ramps must be broken up into sections called ramp runs. Measurements for flat landings, which are required at the top and bottom of each ramp run, and for changes in direction at landings are also defined. Ramp width and handrail requirements are also specified.