What's wrong with new cycle helmet law

News of a helmet law being passed in Jersey has re-opened the debate about the need for such laws. We attempt to understand some of the complex arguments.

Talking about cycle helmet wearing and the effectiveness of laws to make it compulsory is always difficult. Any discussion tends to focus attention on a very small proportion of the most serious injuries resulting in a public misperception that the relative risks of cycling are high compared to similar activities.

Last month the parliament in Jersey passed a law requiring all children under 14 to wear cycle helmets. The Scrutiny Office in Jersey commissioned a consultancy report from The Transport Research Laboratory (TRL) to "review the literature relating to the proposed legislation and its likely effects on cyclist injuries, and cycling activity"

Complex science

There is a complex array of factors in understanding the dynamics of any cycle crash and the medical outcomes. Another set of factors affect the severity of impacts and the likelihood of a crash happening. Further, when considering public policy, comparisons between potential health benefits to millions need to be weighed against changes in injury severity for relatively few people.

In a recent article for the British Medical Journal, Ben Goldacre and David Spiegelhalter concluded "In any case, the current uncertainty about any benefit from helmet wearing or promotion is unlikely to be substantially reduced by further research".

Given the complexity of the analysis of cycle helmet benefits the TRL press release expressed a surprisingly high level of certainty "that legislation requiring the wearing of cycle helmets in Jersey will prevent head and brain injuries". It is unfortunately very common for research press releases to overstate results in a way that leads to mis-information and confusion. Most of the press comment is based on this press release not the content of the TRL report.

Pros and cons of helmet legislation

The actual TRL report concluded that the legislation "can be expected to have a beneficial effect on the injury rates of those impacted by the legislation, especially in collisions that do not involve motor vehicles". That is actually a weak conclusion because there was no attempt to measure how big the total effect of the legislation might be.

Many people claim that introducing compulsory helmet legislation tends to put people off cycling by encouraging a climate of fear due to over-emphasizing the risks of serious injury.

There are considerable health benefits from more people cycling as shown in the Mayor's of London Infrastructure Plan 2050 consultation documents.

This table illustrates the potential impacts on Londoner's health assuming different patterns of travel, measured in potential years of good health (DALYs). More cycling is associated with better health.

In Australia, where cycle helmets have been compulsory in most areas since 1990's, Piet de Jong, professor of Actuarial Studies at Macquarie University has developed a model to evaluate helmet laws. He compared the dis-benefits of less cycling due to a compulsory helmet law with the potential injury reduction benefits of a reduction in injury severity. He concluded that only under extreme, theoretical circumstances do mandatory helmet laws not end up costing the healthcare system more from long term ill health due to less physical activity.

Crucial questions

The crucial question is: do compulsory helmet wearing laws reduce cycling or not? The TRL report asserts that if these reductions occur "they are likely to be small and short term". This is important because if cycle use falls after a law it is difficult to tell if a drop in the number of injuries after legislation is only due to a fall in cycling or to a protective effect of helmets. It also leads to a conclusion that  there are no long term negative health effects.

The TRL report accepts at face value recent Australian research casting doubt on the observations of a fall in cycling after compulsory helmet wearing laws were introduced. Therefore TRL conclude that there are no health impacts.

They also base their conclusions about the benefits of helmet legislation on other research some of which does not consider differences in cycle usage and so cannot distinguish between protective effects and usage effects. TRL refrain from evaluating how effective helmet legislation is in reducing injuries or injury rates in the real world (footnote p.30). Instead they concentrate on bio-mechanical predictions of helmet effectiveness that are not linked real injury data.

Do compulsory helmet laws lead to less cycling?

How good is the Australian research from Olivier et al. (2013) suggesting no fall in cycle use resulting from helmet laws?

A number of recent research papers from the University of New South Wales have suggested that there was no long term fall in cycle use when helmet laws were introduced in 1991.

The examination of changes in cycle use in New South Wales depends on two assumptions. Firstly that counts taken in September 1990 (Australian spring time) are comparable with those taken in April 1991 (Australian autumn) because it is thought that weather is likely to be the same. Reading the original research reports shows a significant difference in actual weather during data collection times. The subsequent yearly surveys show a consistent decline in cycling.

Secondly data missing from the first survey is estimated by comparing one set of observations where the instructions were to not record anyone over 20 years old with observations in later years where the instructions were to record all adults of any age. The estimated data is bound to be incorrect and to lead to false conclusions.

Data table showing (in red) data estimated by comparing some counts excluding most adults with counts including all adults.

There may be other problems with the recent reassessment of the 1990s data which have yet to come to light. It is, however, difficult to assume that the observed 47% fall in children being allowed to cycle in New South Wales did not have long term impacts on the amount of cycling of those children and their families in later years.

Arguments continue

As we noted at the beginning, it is unlikely that science can deliver a definitive answer to the evaluation of the benefits, if any, of helmet legislation. The arguments and confusion will continue.

The TRL report only became available a few hours before the States of Jersey voted for a law forcing children under 14 to wear helmets while cycling. It is unfortunate that the deputies did not have more time to subject the report to proper scrutiny.

CTC, the national cycling charity, came to the conclusion that Jersey's under-14 helmet law "will harm public health and the island's reputation for family cycling".


The header picture is a screenshot from Halfords' excellent #getonyourbike advert


  • By EVLndn at 4:33pm 14 August 2014

Very interesting article/opinion reporting factors regarding wearing helmet that are commonly ignored. The title is 'Why it makes sense to bike without a helmet':



Such a difficult debate, and an almost impossible one to answer. As a cycling instructor I get asked about it so frequently, very forcefully by the HGV drivers I teach: "All cyclists should wear helmets!" My answer is usually that the helmet question detracts from more important debates on road safety - what will really keep you safe? Is it wearing a helmet? Or is it riding in a safe, responsible and predictable manner? Can we please have more access to free cycle training (or better publicity of the fact that this exists) and compulsory cycle training for professional drivers? 

I had an accident last week where I fractured my jaw and smashed in my chin. A helmet would not have helped me in the least. Yet the first question the ambulance man asked me was "Why aren't you wearing a helmet?" *Sigh*

  • By KatieP at 6:13pm 14 August 2014

If cycle helmets were compulsory it would put me off cycling - and I've been cycling for years! Maybe LCC should try doing an opinion poll of cyclists?

I crashed this morning and judging by the state of my helmet afterwards, a big chunk broken off & deep scratches, am sure it saved me from more serious outcome. Don't risk not wearing one!!
  • By neilt17 at 7:36pm 14 August 2014

This is interesting article about the usefulness or otherwise of wearing a cycle helmet: http://www.cyclehelmets.org/1209.html

  • By pfsc at 8:00pm 14 August 2014

It is so rare to read a discussion based on an "evidence based" study with its critique, normally I listen to dial-in shows or read comments based on numerous superstitions, faith, belief or prejudices held about every type of topic.

So well done LCC for this approach to informing a discussion.

I read about a UK study that said cars give riders without helmets a wider berth than those with helmets. Do you have access to this study and could you do a similar critique?

For the record I ride to work everyday, stop at red lights, give hand-signals and never wear a helmet.

Having lived in NSW, one cannot go for a casual cycle because of the ferocity of the sun and risk of unprotected severe skin burning. Distances too are a lot greater than Europe so there are a lot of variables to consider when constructing a null hypothesis about cycling in NSW that is relevant to London.



  • By Shannon at 1:40am 15 August 2014

Cards on the table, I haven't worn one in many years. There is so much heat in this debate, I really recomend going to www.cyclinghelmets.org website for some clarity. It's by the Bicycle Helmet Research Foundation (type in full, or you will be sent to a shop that sells them).They are an international organisation offering policy makers the most recent academic papers and analysis on the topic. It seems to me that there is a lot of lazy or sensational journalism informing the public discourse. Particularly with the helmets=safety lobby. The trouble is that it's a big site and can take hours to read. Worth it though. That said, I'd probably recomend them to the inexperienced or unskillful rider at first. In the longer term, there are many solid reasons not to use them. Counterintuitive, but true. Jersey will make for an interesting case study. From what I understand, the under 14 cohort will experience a rise in KSI's. More kids will never learn to enjoy riding a bike. A group of those who are overweight and inactive from a young age, will go on to get the avoidable lifestyle diseases in their middle age. It's a shame that it will take time for the evidence to come through.

  • By 5jt at 7:47am 15 August 2014

Well done LCC for tackling this difficult topic so carefully. 

The article refers to weak Australian data on the effect of mandatory helmet laws. I have read of better data from New Zealand that shows a strong effect of suppressing cycling.

Riding without a helmet is widely taken as evidence of negligence and, by extension, of culpability in a collision. It is an important component of blaming victims.

Let’s have a counteroffensive to expose the arguments and provoke debate. Let’s campaign for a ban on cycle helmets on the public highway

It would be a spoof, but it’s a simple case. Wearing a helmet provides a small personal benefit. But the sight of helmeted cyclists in high-vis deters people from using bikes, causing a great harm to public health.  

In the real world, that case should probably fall to the libertarian argument. Given large uncertainties in the data, riders should make their own choices. But it would be satisfying to see the helmet champions falling back on the libertarian case.

And it might just do something to reduce victim blaming. 

  • By EVLndn at 8:18am 15 August 2014


'I read about a UK study that said cars give riders without helmets a wider berth than those with helmets. Do you have access to this study and could you do a similar critique?' 


Here --->  


  • By Kie7077 at 10:39pm 15 August 2014

I am sick of the helmet debate already.


It scares people off of cycling.


To cyclist: Why aren't you wearing a helmet.

Corrrect reply: Why aren't YOU wearing a helmet.


When drivers and pedestrians all have to wear helmets by law then we can talk about cyclists wearing helmets, otherwise sincerely STFU ALREADY.

Compulsory helmet wearing is counterproductive, so I hesitate to wade in..although..

Armouring up to try fend off tons of fast, incoming vehicles is a self-defeating pursuit..Unless.. the government want to pay for our 'Ironman' suits, well, then it would be churlish to say no, eh? :-)

After all, it will save us when we visit Jersey, and they try to burn us in 'Whicker Men'. ;-)

This post was edited by mikeybikey at 12:32am 17 August 2014.

  • By bigpete at 10:38am 19 August 2014

Sports riding has done much harm by normalising the wearing of special equipment (including that ultimate talisman, the helmet) when going for a bike ride.

If H.G. Wells were alive today I'm sure he'd be saying "Every time I see an adult wearing normal clothes on a bicycle, I no longer despair for the future of the human race."

  • By AKB at 6:46pm 19 August 2014

Well I am from Melbourne and have lived in the UK for the last 12 months.  Compared to there, the UK is a cycling paradise - despite the common view here, and despite the weather. 

I've ridden >6,000km in the last 12 months in London, while all my riding in Australia over the previous five years was on stationary bikes in the gym.  For me the compulsory helmet laws absolutely contributed to my decision stay off the road.

If you want to look at helmet laws in Australia, just google 'Melbourne cycle hire success' to see what I mean.  Virtually anyone with an opinion, commenting on the dismal failure of the scheme, points at mandatory helmet laws as the number one cause.  People routinely call for helmet laws to be relaxed just so the scheme is actually used.

It's a bit old, but a stat quoted from an article in 'The Age' from 2010, had less than 70 trips per day being made on Melbourne's cycle hire scheme - for the entire city (4 million population).  As a recent resident, who worked in Melbourne five days a week for years, I can honestly say that I never saw a single person use the bikes.

  • By annie at 1:57pm 31 August 2014

There is as yet no Class A evidence that the wearing of cycle helmets reduces morbidity or mortality. There have been no studies that actually compare like for like. The behaviour of people wearing definitive cycling wear, including the helmet,  like a professional in a race or tour; the types of cycles they ride; their speed and road usage is in fact (proven to be) quite different from non- cycle- uniform wearers.

No study has been done on having the same people ride with and without helmets over a time period.

Helmets only prevent head injuries. Most cyclists in London are not in fact killed by isolated head injuries.

I like wearing my helmet crossing London every day. I also like the freedom in other places not to have to wear one.

I saw a toddler the other day, on a little one-foot- scooter, and his helmet was so large he could hardly balance with it, it was the width of his shoulders! Sad.

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