Increasing the conspicuity of cyclists at night by using bicycle lights and clothing to highlight their biological motion to oncoming drivers

Reduced conspicuity is an important contributing factor to increased motor vehicle-bicycle crashes and cyclist fatalities at night. This study explored ways of making night-time cyclists more conspicuous to oncoming vehicles through cyclist clothing options and bicycle light position. Fifteen young participants (M = 29.1 ± 4.5 years) drove a closed-road at night and indicated when they first recognized a cyclist pedalling in place at the roadside, facing the approaching vehicle. The bicycle had a static forward-facing white light located either on the handlebars or the helmet and wore one of five clothing configurations: fluorescent vest, retroreflective vest, retroreflective ankle strips, retroreflective vest plus retroreflective ankle strips, retroreflective vest plus biomotion retroreflective strips. There was a significant effect of light position (p < 0.001) and clothing (p < 0.001), where recognition distances were longer when the light was helmet-mounted and when retroreflective strips were worn on the lower legs to highlight the cyclist's biological motion compared to either of the vest conditions. There was also a significant interaction between light position and clothing (p = 0.007) such that the benefit of retroreflective strips was greater when the bicycle light was helmet-mounted rather than on the handlebars. Importantly, the benefits of leg markings were apparent even when positioned at the ankles alone. These findings highlight that retroreflective material is most useful for improving cyclist conspicuity at night when positioned on cyclists’ lower legs, particularly the ankles (highlighting the cyclist's pedalling motion), rather than on the torso, and have important practical implications for maximising cyclists’ conspicuity and hence safety on night-time roads.