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bicycle safety devices - effects on vehicle passing distances

three devices designed to increase bicycle safety have been evaluated on rural and suburban roads. two devices, a swedish flag and a finnish disc, are mounted on the rear carrier or frame of the bicycle and project horizontally into the road on the offside. these devices are intended to increase the distances at which vehicles pass the bicyclist. the third device tested was a fluorescent waistcoat which is used as a conspicuity aid. a camera mounted on the rear carrier of a test bicycle allowed photographs of overtaking vehicles to be taken. from the photographs the passing distances were obtained. no attempt was made to assess the contribution the devices made to the conspicuity of rider and bicycle. accident risks when overtaking and in other manoeuvres could be reduced if this contribution is substantial. results showed that small but statistically significant increases in average passing distances occurred. the swedish flag and finnish disc devices produced on average the largest effects, significant increases being found in both rural and suburban areas. the fluorescent waistcoat produced a significant increase at only one of four sites. the proportion of close passes (less than 1 m from the rider) did not show consistent decreases for any device.(a)

Author Watts, GR Pages 15
Date 01/01/1979 Reference SR512
ISBN 0305-1315 ISSN 0305-1315

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