Over two million people in the United States use a wheelchair for their primary means of mobility and rely on functional and accessible sidewalks to participate in their communities. The Americans with Disabilities Act Accessibility Guidelines (ADAAG) related to roughness are subjective and not measurable which results in public pathways with many bumps and cracks, which can lead to harmful whole-body vibrations (WBVs) for wheelchair users. ISO standard 2631-1 specifies health guidance caution zones for how much vibration exposure can be dangerous, but it is unknown how surface roughness can affect the amount of vibration that wheelchair users are exposed to. To develop a standard for surface roughness, subjective ratings and root mean square (RMS) accelerations were gathered and analyzed from subjects traveling over surfaces with various roughnesses in their own wheelchairs. As expected, the results show that as surface roughness increased, RMS accelerations increased and subjective ratings decreased. Some surfaces generated RMS accelerations above the ISO health guidance zone and/or were rated as unacceptable by more than half of the subjects suggesting that some surfaces are causing harmful vibrations and discomfort to wheelchair users. Based on the combination of RMS data and subjective feedback from wheelchair users, the authors are proposing a roughness index threshold of 1.20 in/ft for a 5m moving average window, and 0.60 in/ft for a 100m moving average window. This proposal will allow for small “transition” rough areas such as detectible warning pads at crosswalks but will restrict the roughness of the overall long surface or city block.