Pervious Concrete Accessible Pathways: Usability for Individuals with Disabilities

The Americans with Disabilities Act Accessibility Guidelines describe accessible routes as needing to be firm, stable, and slip-resistant. No mention is made of route smoothness. While the U.S. Access Board provides recommendations regarding coefficient of friction values for horizontal surfaces and ramps, it notes that research is needed regarding both slip-resistance and smoothness before any requirements can be considered. The slip-resistance and smoothness characteristics were studied for a material increasingly used for accessible routes, pervious concrete. A total of 9 pervious concrete pathways in the community were included in the study, along with 3 pathways constructed of standard concrete. Coefficient of friction values were measured using the Brungraber Mark IV device. Pathway roughness was measured with a rolling profilometer, the SurPRO 4000, used by many concrete industry and roadway inspection professionals. Data was taken to determine the pathway International Roughness Index, and the recently-developed Wheelchair Pathway Roughness Index. Additionally, a lightweight manual wheelchair, typical for an active wheelchair user, was instrumented with accelerometers to measure the whole-body vibration (WBV) experienced by a simulated wheelchair user. Data was taken at two velocities, 0.75 m/s and 1.00 m/s, over a 30m pathway. Coefficient of friction values were found to be in compliance with ADAAG recommendations, except in one location where sealant had been recently applied. Pathway roughness values were similar to roadways considered in good condition. Pervious concrete roughness values were both above and below the values of the control pathways. WBV levels indicated that travel on pervious concrete pathways is safe for wheelchair users when using the ISO 2631 to determine vibration health hazards, especially when research regarding actual daily wheelchair travel in the community is taken into account.