Image: TfL via Flickr
The results of a new study suggest that cyclists are more than 50% less likely to be involved in a collision with a motor vehicle when wearing high-visibility clothing.
Described as the the first randomised controlled trial (RCT) looking at the safety effect of hi-vis clothing for cyclists, the Danish study compared the number of self-reported accidents for two groups – one group (3,402 cyclists) wearing yellow hi-vis (pictured below) and the other without (3,391 cyclists) – over a one-year period.
The study set out to test the hypothesis that ‘the number of cyclist accidents can be reduced by increasing the visibility of the cyclists’.
In total, the ‘accident rate’ (accidents per person per month) was 47% lower among those wearing a hi-vis jacket – rising to 55% when it comes to collisions involving cyclists and motor vehicles.
The safety effect was greater in winter (56%) than in summer (39%), and also greater in daylight hours (51%) than overall (47%).
The study was non-blinded*, and the number of reported single accidents (involving no other vehicle or individual) was significantly lower in the test group than in the control group.
The researchers, from the Traffic Research Group at Aalborg University, say this is likely to be a result of a ‘response bias’, since the hi-vis jacket was not expected to affect the number of single accidents.
To compensate for this bias, a separate analysis was carried out which reduced the effect of the jacket from 47% to 38%.
*A blind — or blinded — experiment is one in which information about the test is masked (kept) from the participant, to reduce or eliminate bias, until after a trial outcome is known. In this study the participants knew what was being tested, and as such it was a ‘non-blinded’ study.