The purpose of a rider conspicuity law is to increase use of conspicuity aids such as reflective accessories or high-visibility clothing. Improving bicyclist conspicuity is intended to make bicyclists more visible to motorists and to enable motorists to see and avoid collisions with bicyclists. Overall, conspicuity measures may improve detection and recognition of bicyclists by motorists, (Kwan & Mapstone, 2009). Prati examined crash data from Italy after a law was passed requiring bicyclists to wear high-visibility clothing and found no evidence of a relationship between the legislation and a change in crashes (Prati, 2018).
A comprehensive approach to improving bicyclist conspicuity should include improving the ambient roadway lighting and creating safe and predictable places spaces for bicyclists to ride, where drivers expect to see them (Raborn et al., 2008). While it is possible that improvements in conspicuity may have a small effect on driver detection of cyclists, it may not prevent crashes. Agencies are instead encouraged to consider how to separate pedestrians and bicyclists from the risk of motor vehicles as with a Safe System Approach.