The use of conspicuity aids by cyclists and risk of crashes involving other road users: a protocol for a population based case-control study

Background: Regular cycling has been shown to improve health and has a role in tackling the threats posed by obesity and inactivity. Cycle collisions, particularly those involving motorised vehicles, can lead to significant mortality and morbidity and are currently a barrier to wider uptake of cycling. There is evidence that the conspicuity of cyclists is a factor in many injury collisions. Low-cost, easy to use retro-reflective and fluorescent clothing and accessories ('conspicuity aids') are available. Their effectiveness in reducing cycling collisions is unknown. The study is designed to investigate the relationship between the use of conspicuity aids and risk of collision or evasion crashes for utility and commuter cyclists in the UK. Methods/Design: A matched case-control study is proposed. Cases are adult commuter and utility cyclists involved in a crash resulting from a collision or attempted evasion of a collision with another road user recruited at a UK emergency department. Controls are commuter and utility cyclists matched by journey purpose, time and day of travel and geographical area recruited at public and private cycle parking sites. Data on the use of conspicuity aids, crash circumstances, demographics, cycling experience, safety equipment use, journey characteristics and route will be collected using self-completed questionnaires and maps. Conditional logistic regression will be used to calculate adjusted odds ratios and 95% confidence intervals of the risk of a crash when using any item of fluorescent or reflective clothing or equipment. Discussion: This study will provide information on the effectiveness of conspicuity aids in reducing the risk of injury to cyclists resulting from crashes involving other road users.