Motorcyclists have been shown consistently to be at a high risk of being involved in road collisions (Wulf, Hancock & Rahimi, 1989; Chesham, Rutter & Quine, 1991; Horswill & Helman, 2003), and often such collisions involve another vehicle violating the path of a motorcycle at a junction or intersection. It is known that two key factors contributing to such collisions are the relatively low conspicuity of motorcyclists, and the relative difficulty that other road users have in judging the time it will take a motorcycle to reach their position (time to collision or TTC) (e.g. Wulf et al., 1989; Horswill, Helman, Ardiles, & Wann, 2005).
Here we report findings from a roadside observation study in which participants were invited to observe a section of road (60kph limit) in Albany, Auckland, New Zealand, while a trial motorcycle was ridden past their position (average approach speed 55.7kph) displaying either a single headlight, a "V" lighting configuration with the headlight and LED lighting on the raised mirrors of the motorcycle, or a "Y" configuration which added LED lighting on the front forks. At night, the motorcycle was detected approximately three-quarters of a second earlier with the "V" lighting and approximately one and a quarter seconds earlier with the "Y" lighting than with the headlight alone, but only when the participants were instructed to search the scene for motorcycles (as opposed to reporting the things in the scene that grabbed their attention). At night the "V" and "Y" lighting also led participants to report longer "˜smallest acceptable gaps" (by approximately half a second and three quarters of a second respectively) in front of the oncoming motorcycle than they did in the "˜headlight only" condition. Daytime detection was much earlier than night time detection, and detection was much earlier when participants were asked specifically to search for motorcycles.
