Why do drivers close pass cyclists?

close pass

Nobody knows for certain why some drivers insist on overtaking cyclists too close. However, it’s not because they’ve failed to spot the person on the bicycle.

If this sounds counter-intuitive, take note of Dr Ian Walker, Senior Lecturer in Psychology at Bath University – his research focuses particularly on the safety of vulnerable road users and their interactions with motorists, considering such issues as road user attitudes and stereotypes, and the roles of urban design and policy in affecting vulnerable road users’ safety. Dr Walker has conducted research to monitor cars when they overtake cyclists wearing a variety of high-visibility and disruptive pattern clothing.

Ian Walker high-viz

Dr Walker found that outfits in the study (except the one with the word ‘police’) were treated exactly the same, almost to the centimetre.

It seems likely that, ‘punishment passes’ aside, close overtaking is a product of ineptitude on the part of drivers. It doesn’t help that so few people in Britain now cycle. When we travelled to the Netherlands last year to shoot our documentary about road danger, Stop Killing our Children, we spoke to Vim Bot – national and international policy adviser for the Fietsersbond, the Dutch Cyclists’ Union:

“Foreign observers notice that behaviour of car drivers in the Netherlands is better than in their own country, and certainly than that in Britain – I think it has to do with the fact that cycling is part of everyday culture in the Netherlands. It means that most car drivers will cycle themselves, or they will have cycle as a child, or they will have their children cycling so they know that there are cyclists everywhere.”

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Cars can rob drivers of their humanity

Australian research on attitudes towards cyclists last year found that 49 per cent of non-cyclists viewed people who ride a bike as non-human, according to the study which was published in the journal Transportation Research.

The research concludes that studies have shown that dehumanisation is associated with increased antisocial behaviour and aggression toward a variety of groups, and that it does so by removing normal inhibitions against harming others. Attitudes were measured by asking people to respond with how much they agreed with statements such as “I feel like cyclists are mechanical and cold, like a robot.”

The study also sought to connect dehumanisation to aggressive behaviour toward cyclists — which was measured by asking respondents if they had ever driven close to a cyclist on purpose, or behaved aggressively in another way.

The study found that the more dehumanisation a person admitted to, the more likely that they  behaved aggressively towards a person on a bike. Driving, it seems, robs many of their humanity.

The research team did not make specific recommendations about how to improve attitudes toward cyclists, but speculated that Australia’s mandatory helmet law may exacerbate the problem by obscuring riders heads and faces. It’s a hypothesis that’s supported by Dr Ian Walker, who 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 lorry 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. 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 more space when passing.

Across the board, drivers passed an average of 8.5 cm closer with the helmet than without. According to Dr Walker: “This study shows that when drivers overtake a cyclist, the margin for error they leave is affected by the cyclist’s appearance”.

The ethical choice

The ETA was established in 1990 as an ethical provider of green, reliable travel services. 30 years on, we continue to offer cycle insurance, travel insurancebreakdown cover  and home insurance while putting concern for the environment at the heart of all we do.


  1. Owain


    One thing that I have found makes a difference, not that I would necessarily recommend it to others, is to wobble on the bike. People have given me a lot more space when I do this

  2. Sion Whellens


    Cycle Training UK cited similar evidence on distance v helmet wearing, but found that high vis/athletic cycling gear in general was associated with motorists passing much closer.

  3. John Richter


    Thanks for forwarding such an interesting and relevant study on cycling safety

  4. Dr John Heathcote


    I live and cycle in the north of Scotland, where there are a lot of Dutch tourists in summer. Dutch camper-vans, often with a bike on the back, are worse than average when it comes to passing close, is my subjective assessment.

    I wear a helmet. Whether hit causes the close passes I don’t know, but it has meant that the three times I have come off for other reasons, I have escaped without head injury. On two of the occasions I was knocked off by an inattentive fellow cyclist.

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