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Will a Cycle Helmet Protect Your Head In an Accident?

View profile for Malcolm Underhill
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“Cool kids wear lids.”  “Protect your head or end up dead.”  “Keep calm and helmet on.”  These are just some of the catchy slogans associated with promoting cycle helmets.  Those in favour of making cycle helmets compulsory have been campaigning for years for the British government to change the law.  So far, despite the often-positive evidence, cycle helmets remain voluntary in the UK. 

Is it time for the law to be reviewed?  Can wearing a cycle helmet protect a rider from serious injury or death?  And if so, why is there reluctance to make the wearing of helmets law?

Cycle helmets in the UK – the current situation

At present, there is no requirement for any cyclist, regardless of age, to wear a cycle helmet[1].

There is also strong support from certain lobby groups for the status quo to remain.  Cycling UK is unequivocally opposed to cycle helmets being made compulsory[2].  This is a point that I[CM1]  will examine in further detail later.  But first, it is important to examine the facts surrounding how head injuries affect cyclists.

Cycling head injury statistics

According to the latest statistics, 113 people died on the road, and 3,401 were seriously injured in 2014[3].  Hospital data showed that over 40% of cyclists, and 45% of child cyclists, suffer head injuries.  A study of 116 fatal cyclist accidents in London and rural areas found over 70% of the cyclist fatalities in London had moderate or severe head injuries, rising to 80% for those killed on rural roads.  The head injuries suffered ranged from fatal skull fractures and brain damage to minor concussion and cuts[4].

These statistics show that head injuries play a significant part in the death and serious injury of cyclists.  Before looking at the arguments for and against cycle helmets, it is useful to see how other countries who have made cycle helmets compulsory, measure against UK statistics.

New Zealand

Mandatory use of cycle helmets came into force in New Zealand in 1994.  All ages are subject to the law and fines can be issued for non-compliance[5].  The law was largely brought about by Rebecca Oaten, dubbed “The Helmet Lady” by local media.  Her son Aaron was left permanently brain damaged after a car struck his bicycle when he was 12 years old.  He was flung over the handlebars, his head striking the gutter[6].  A doctor informed her that if Aaron had been wearing a safety helmet, he would not have suffered brain damage.

Ms. Oaten spent six years campaigning for cycle helmets to be made compulsory, often visiting up to four schools a day to give talks to students. 


Australia was the first country in the world to make the wearing of cycle helmets compulsory, phasing the law in between 1990 and 1992.  The regulation was backed by massive public support.


In January 2017, new laws made it compulsory for children under 12 to wear a cycle helmet[7].

United States

The law varies by state and localities.  For example, the wearing of cycle helmets is compulsory for people of all ages in Seattle but mandatory only for those aged under 16 years in Charlotte, North Carolina[8].

The Netherlands

Interestingly, the country with the lowest number of cyclist fatalities in the world[9] does not make cycle helmets compulsory.

What does the research say about cycle helmets and the protection they offer?

There is a wealth of research surrounding the protection afforded by cycle helmets against brain injury.  Unfortunately, none is conclusive, and the methodology of some well-known tests has been questioned[10].

Speaking to The Guardian in 2015, Marco te Brömmelstroet, director of the Urban Cycling Institute of the University of Amsterdam dismissed much of the research around the protective element of cycle helmets. 

“There only are a limited amount of scenarios in which helmets provide protection. “That is when the cyclist falls without being involved in a crash. But when you collide with a car that drives faster than 20 miles an hour, a helmet does nothing to save you.”[11]

“It is important to realise that wearing a helmet can have adverse effects. It does not always make cycling safer. Cyclists with helmets are liable to take more risks because they consider themselves safe. And an English study has shown that motorists give considerably less space whilst overtaking cyclists with helmets than when they overtake cyclists that go bareheaded. If you look at it this way, wearing a helmet could lead to more injuries than not wearing one.”[12]

One study in 1989 by epidemiologists Diane C. Thompson and Dr. Robert Thompson concluded that bicycle helmets reduced the chances of head injury by 85%[13].  However, the research was considered flawed due to the methodology used.  The researchers compared the low, helmet-wearing habits of head-injured bicyclists with the high, helmet-wearing habits of bicyclists who had sustained other bodily injuries.  Because of the discrepancy in helmet wearing rates, with the bodily-injured group wearing helmets more frequently than the head-injured group, the Thompsons concluded that helmets reduced head injuries.

But, in an article by Shaun Lopez-Murphy in Momentum magazine, the author quoted Dr. Dorothy Robinson, a leading bicycle helmet researcher at the University of New England, who criticised the Thompson paper because of the comparison group used.

“The whole idea of a [comparison] group is that it should represent the general population, she wrote to me in an email. If the study had used the low, helmet-wearing rate of the general, child bicycling population seen in Seattle at the time, there would have been very weak evidence showing that helmets reduced head injuries”.[14]

Dr. Robinson’s statement has been given further gravity by the fact that no research in the numerous studies on cycle helmets that followed the Thompson paper ever came close to replicating the 85% figure.  A 2011 study by Rune Elvik concluded that helmets did reduce brain injury, but by 30%[15].

The introduction of compulsory cycle helmets in New Zealand and Australia in the 1990s did lead to a drop in bicycle injuries and deaths.  But, as Dr. Robinson pointed out in her paper[16] other road-safety initiatives, such as clampdown on speeding and drink-driving had led to a decline in all road accidents.

Theories behind why cycle helmets are not more effective

There are several theories about why cycle helmets do not provide greater protection against traumatic head and brain injury.  The main argument is that both cyclists and motorists take more risks if a cyclist is wearing a helmet.  A 2012 Norwegian study indicated that at least part of the reason why helmet laws do not appear to be beneficial is that they disproportionately discourage the safe behavior in cyclists, especially when it comes to speed[17].  It is also thought that car drivers pass closer to cyclists wearing helmets a theory popularised by Dr. Ian Walker in 2006[18]; however, this theory has been debunked by recent studies[19].

The jury is still out on whether cycle helmets reduce the number of head and brain injuries occurring.

The ‘cycle helmet paradox'

The greatest argument for not making cycle helmets compulsory is this; in countries that have introduced mandatory helmet wearing, the number of cyclists has fallen.

In Australia, helmet laws caused head injuries to fall by 11% to 21%.  But overall cycling fell by 30% to 60%, suggesting that those who continued to cycle were more at risk of receiving a head injury.[20]  This could be attributed to the ‘safety in numbers’ theory which is explained below. 

Cycling UK states on its website that, “Evidence shows that the health benefits of cycling are so much greater than the relatively low risks involved, that even if these measures caused only a very small reduction in cycle use, this would still almost certainly mean far more lives being lost through physical inactivity than helmets could possibly save, however effective.”[21]

A decrease in the number of cyclists could also put those continuing to cycle at greater risk because of the “safety in numbers” theory.  According to Shaun Lopez-Murphy’s article[22], Peter Jacobsen, the most cited researcher regarding this theory, found in 2003 that motorists were less likely to collide with a bicyclist if there were more people riding bicycles – no matter the size of the city, the intersection, or the time of year.  Since it’s been shown that helmet laws are associated with a decrease in the number of bicyclists, the safety in numbers theory suggests that when there are fewer bicyclists on the road, motorists are more likely to collide with them[23].

An article by Elisabeth Rosenthal in the New York Times summed up the paradox perfectly:

“Many researchers say, if you force or pressure people to wear helmets, you discourage them from riding bicycles.  That means more obesity, heart disease, and diabetes.  And — Catch-22 — a result is fewer ordinary cyclists on the road, which makes it harder to develop a safe bicycling network.  The safest biking cities are places like Amsterdam and Copenhagen, where middle-aged commuters are mainstay riders, and the fraction of adults in helmets is minuscule”[24].


With the current research available and the difficulty in measuring for the ‘cycle helmet paradox,' it is impossible to say whether the wearing of a helmet protects cyclists against catastrophic head injuries.  And until there is more concrete evidence available, it is unlikely that the British Government will make the wearing of cycle helmets compulsory anytime soon. 

Have you sustained a serious injury while cycling?

At IBB, our personal injury team, led by accredited brain injury lawyer, Malcolm Underhill, has the expertise and knowledge to advise and represent those who have suffered a traumatic brain injury and wish to claim compensation. To talk about how we might be able to help, please phone us on 0333 123 9099, email us at  or fill in our contact form.  Any discussions you have with us will be in the strictest of confidence

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[4] Ibid








[12] Ibid













 [CM1]I presumed from the email that this is going to an external publication with Malcolm as the author.

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