High vis clothing doesn't make cars pass you more safely, says new study

If you feel like some drivers will pass too close no matter that you wear and that you’re being given less space on the road than you used to, a new study says you’re right, and indicates very strongly that you’re not safer if you wear high-vis in the daytime.

Researchers from the University of Bath and Brunel University found that no matter what clothing a cyclist wears, around 1-2% of drivers will pass dangerously close when overtaking. They also found that compared to Transport Research Laboratory findings in 1979, drivers today on average pass 61cm (2ft) closer to cyclists - 118cm compared to 179cm.

The researchers conclude that there is little a rider can do, by altering their outfit or donning a high-visibility jacket, to prevent the most dangerous overtakes from happening. Instead, they suggest, if we want to make cyclists safer, it is our roads, or driver behaviour, that need to change.

The research was conducted by Dr Ian Garrard from Brunel University and the project led by Dr Ian Walker from Bath University. Ian Walker is famous as the sometime wig-wearer who discovered in 2006 that cyclists are afforded more space by drivers if they appear to be female or are not wearing a helmet.

In this study, the two Dr Ians were trying to find out if drivers gave cyclists more room depending how skilled and experienced they looked. They expected that drivers would give more space to a rider who seemed inexperienced and less space to a rider who looked highly skilled.

The range of outfits worn during the research

Dr Garrard used an ultrasonic distance sensor to record how close each vehicle passed during his daily commute in Berkshire and outer London. Each day, he chose one of seven outfits at random, ranging from tight lycra racing cyclist clothes (signalling high experience) to a hi-viz vest with “novice cyclist” printed on the back (signalling low experience).

He sometimes also wore a vest that said he was video-recording his journey, or a vest modelled on a police jacket but with “POLITE” printed on the back. He rode the same bike, in the same way, every day and over several months collected data from 5690 passing vehicles.

The vest that mentioned video recording persuaded drivers to pass a little wider on average, tallying with anecdotes from helmet-cam users that drivers behave better when they know they are being recorded. However, there was no difference between the outfits in the most dangerous overtakes, where motorists passed within 50 cm of the rider. Whatever was worn, around 1-2% of motorists overtook within this extremely close zone.

Dr Ian Walker said: “Many people have theories to say that cyclists can make themselves safer if they wear this or that. Our study suggests that, no matter what you wear, it will do nothing to prevent a small minority of people from getting dangerously close when they overtake you.

“This means the solution to stopping cyclists being hurt by overtaking vehicles has to lie outside the cyclist. We can’t make cycling safer by telling cyclists what they should wear. Rather, we should be creating safer spaces for cycling – perhaps by building high-quality separate cycle paths, by encouraging gentler roads with less stop-start traffic, or by making drivers more aware of how it feels to cycle on our roads and the consequences of impatient overtaking.”

The researchers point out that while they found that wearing high-visibility clothing made no difference to the space left by overtaking drivers, they did not try to find out if it made cyclists more visible at junctions or at night.

However, they note that there is surprisingly little evidence that high-visibility clothing for cyclists and motorcyclists offers any safety benefits in daytime. This would further support the idea that there is no easy fix for riders’ safety from asking them to wear bright clothing.

The reduction in average passing distance between 1979 and today “could be a result of greater traffic volumes since the 1970s,” say the researchers, “or reduced levels of  bicycling which mean that the average motorist is less likely to have experience of bicycling themselves, and so is less understanding of a bicyclist’s needs.”

It occurs to us that it could also be linked to the increased width of modern cars. A 1979 Ford Escort Mk II was 1570mm wide (5ft 2in) while the modern equivalent Ford Focus is 1823mm wide (5ft 11 1/2in). However, Ian Walker points out that there was no difference in passing distance between wide four-wheel drive vehicles and standard cars in his 2007 study.

The paper - The influence of a bicycle commuter’s appearance on drivers’ overtaking proximities: An on-road test of bicyclist stereotypes, high-visibility clothing and safety aids in the United Kingdom - will be published in the journal Accident Analysis and Prevention.