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Means of making motorcycles more conspicuous

In: HSRI Research Review, Vol. 10, No. 2, Sept.-Oct. 1979, p. 1-21

Authors: Paul L. Olson, Michael Sivak, R. Halstead-Nussloch

Motorcycle accident data suggest that motorcycle-car accidents often occur because the car driver does not perceive the moving motorcycle soon enough. A study was conducted to develop and evaluate various means of making motorcycles more conspicuous. More than 30 conspicuity treatments were developed, and the most promising ones evaluated in day and night tests involving ordinary car drivers on public roads. The tests established which conspicuity treatments effectively deterred motorists from accepting short time (space) gaps. Findings showed that daytime conspicuity of a motorcycle is significantly improved if (1) its normal low-beam headlamp is turned on; or (2) its high-beam headlamp is turned on and is modulating in intensity three times per second; or (3) the motorcyclist is wearing a high-visibility (fluorescent) vest and helmet cover. Nighttime conspicuity is significantly improved when the motorcycle uses additional running lights or the cyclist is wearing a retroreflective vest and helmet cover. Tests also showed that an ordinary motorcycle is usually most conspicuous in the center for the right lane, rather than in the left or right portion of the lane. Cost-benefit analyses indicated that several conspicuity treatments are cost-beneficial. Given that about three out of four motorcycle accidents occur in daytime, one major conclusion drawn from the study is that the most effective means of improving daytime conspicuity (considering performance, cost, and cyclist convenience) is to require motorcyclists to drive during the day with their low-beam headlamp turned on.