Bicyclists who wear protective helmets are more likely to be struck by passing vehicles, new research suggests.

Drivers pass closer when overtaking cyclists wearing helmets than when overtaking bare-headed cyclists, increasing the risk of a collision, the research has found.

Dr Ian Walker, a traffic psychologist from the University of Bath, used a bicycle fitted with a computer and an ultrasonic distance sensor to record data from over 2,500 overtaking motorists in Salisbury and Bristol.

Dr Walker, who was struck by a bus and a truck in the course of the experiment, spent half the time wearing a cycle helmet and half the time bare-headed. He was wearing the helmet both times he was struck.

He found that drivers were as much as twice as likely to get particularly close to the bicycle when he was wearing the helmet.

when drivers overtake a cyclist, the margin for error they leave is affected by the cyclist’s appearance

Across the board, drivers passed an average of 8.5 cm (3 1/3 inches) closer with the helmet than without

The research has been accepted for publication in the journal Accident Analysis & Prevention.

“This study shows that when drivers overtake a cyclist, the margin for error they leave is affected by the cyclist’s appearance,” said Dr Walker, from the University’s Department of Psychology.

“By leaving the cyclist less room, drivers reduce the safety margin that cyclists need to deal with obstacles in the road, such as drain covers and potholes, as well as the margin for error in their own judgements.

“We know helmets are useful in low-speed falls, and so definitely good for children, but whether they offer any real protection to somebody struck by a car is very controversial.

“Either way, this study suggests wearing a helmet might make a collision more likely in the first place.”

Dr Walker suggests the reason drivers give less room to cyclists wearing helmets is down to how cyclists are perceived as a group.

“We know from research that many drivers see cyclists as a separate subculture, to which they don’t belong,” said Dr Walker.

“As a result they hold stereotyped ideas about cyclists, often judging all riders by the yardstick of the lycra-clad street-warrior.

“This may lead drivers to believe cyclists with helmets are more serious, experienced and predictable than those without.

“The idea that helmeted cyclists are more experienced and less likely to do something unexpected would explain why drivers leave less space when passing.

“In reality, there is no real reason to believe someone with a helmet is any more experienced than someone without.

“The best answer is for different types of road user to understand each other better.

“Most adult cyclists know what it is like to drive a car, but relatively few motorists ride bicycles in traffic, and so don’t know the issues cyclists face.

“There should definitely be more information on the needs of other road users when people learn to drive, and practical experience would be even better.

“When people try cycling, they nearly always say it changes the way they treat other road users when they get back in their cars.”

The study also found that large vehicles, such as buses and trucks, passed considerably closer when overtaking cyclists than cars.

The average car passed 1.33 metres (4.4 feet) away from the bicycle, whereas the average truck got 19 centimetres (7.5 inches) closer and the average bus 23 centimetres (9 inches) closer.

However, there was no evidence of 4×4s (SUVs) getting any closer than ordinary cars.

Previously reported research from the project showed that drivers of white vans overtake cyclists an average 10 centimetres (4 inches) closer than car drivers.

To test another theory, Dr Walker donned a long wig to see whether there was any difference in passing distance when drivers thought they were overtaking what appeared to be a female cyclist.

Whilst wearing the wig, drivers gave him an average of 14 centimetres (5.5 inches) more space when passing.

In future research, Dr Walker hopes to discover whether this was because female riders are seen as less predictable than male riders, or because women are not seen riding bicycles as often as men on the UK’s roads.

Just the facts ma’am

11,257 adult cyclists were injured and 109 killed on the UK’s roads in 2004, the latest year for which figures are available. However, for each bicycle accident officially recorded there are as many as 14 more which do not go on police records, and so the number injured is certainly an under-estimate. Being struck by an overtaking car is arguably the most dangerous form of collision for a cyclist, with a particularly high mortality rate.

White Van Man is a danger on roads, research finds

New research has proved what many of us have long suspected: white van man is a danger on the roads.

Drivers of white vans overtake cyclists an average 10 centimetres (4 inches) closer than car drivers, according to new research.

Using a special bike fitted with a video camera and an ultrasonic distance sensor, Dr Ian Walker from the University of Bath has cycled over 300 km (186 miles) in Bristol and Salisbury over the last two months.

During this time he has been overtaken by around 2,500 vehicles, and each time the sensors recorded the type of vehicle and the distance at which it passed the bike.

In total about 200 of these vehicles were white light goods vehicles, which gave an average passing distance of 1.26 metres (just over 4 feet 1 inch).

However, the drivers of the 200 black cars which overtook Dr Walker – chosen for comparison because there was a comparable number with white vans – allowed cyclists an extra 10 centimetres at 1.36 metres (4 feet 5 1/2 inches).

“At the kinds of speeds and distances that cyclists are overtaken on our city streets, reducing the gap between cyclist and vehicle can have life-threatening safety implications,” said Dr Walker, a researcher in the Department of Psychology at the University of Bath.

“Why white van drivers overtake closer is not clear; it could be a range of things, from social or personality factors, to the length and width of the vans, or even the stereotypical machismo of white van man.

“Being able to measure the passing distances that different vehicle drivers give to cyclists and other vulnerable road users is the first step in identifying some of the issues that put them most at risk.

“More than 2,000 cyclists are seriously injured in road accidents each year, and 100 die. By looking scientifically at the issues that compromise their safety we can try and find ways of tackling the root causes of some of these accidents.

“Being hit by an overtaking vehicle is extremely dangerous for a cyclist. If we understood what determines how close drivers get to cyclists as they overtake, we could do something to make collisions less likely, either in the way we construct our roads or, more likely, with advice to drivers about how they should drive and to cyclists about how they should ride.”

Dr Walker will be talking about some of his early research findings at a meeting of the Bath Royal Literary & Scientific Institution, 16-18 Queen Square, Bath, on Tuesday 11 July 2006 (7.30 – 9pm).

The Highway Code advises drivers to give motorcyclists, cyclists and horse riders at least as much room as they would a car when overtaking. It also advises drivers to give these vulnerable road users ‘plenty of room’.

According to the Royal Society for the Prevention of Accidents, every year in this country over 15,000 cyclists are killed or injured in reported road accidents, including more than 2,100 who are killed or seriously injured.

Dr Walker is a keen cyclist and recently completed the journey from John O’Groats to Land’s End.

The research is funded by the Engineering and Physical Sciences Research Council as part of its Transportation Operations and Management research programme.