Introduction: Wheelchair users deploy a variety of strategies to increase their visibility to motorists. Unfortunately, there is no empirical evidence supporting the use of any of these visibility strategies with this population.Objectives: To investigate the effectiveness of four different visibility strategies (i.e., light emitting diode (LED) lighting system, reflective safety vest, orange flag, or control (i.e., black clothing)) for wheelchair users in nighttime and daytime conditions.Methods: Participants were shown videos from the driver's perspective depicting a wheelchair user waiting to cross the street while using one of the four visibility strategies in isolation during nighttime and daytime. Participants indicated when, if at all, they first saw the wheelchair user at the roadside. Results were compared to determine which strategy allowed for the longest reaction time.Results: In nighttime conditions, the most effective strategy was the LED lighting system followed by the reflective vest. Neither the orange flag nor black clothing provided an adequate stopping distance when a vehicle was traveling at 32km/h at night. During daytime conditions, all visibility strategies were effective when a vehicle was traveling at this speed.Conclusions: These results will help clinicians and enable wheelchair users to make informed choices about the best visibility strategies to use.

Keywords: driving; mobility; usability; wheeled mobility aids.