Pros and Cons of Mandatory Bicycle Helmet Laws - What's the Evidence?

A Northern Ireland Assembly's decision to vote in favour of making the wearing of cycle helmets compulsory has re-activated a long standing worldwide debate about the merits of such laws. The British Medical Association has always argued that protective helmets and other headgear is a great way to prevent injuries and save lives. Opponents claim that these laws would discourage bike use and could be detrimental to the nation's health as less people would ride bicycles for exercise and for short trips. Likewise many have argued that the evidence supporting the contention that head gear protect the skull in the event of an accident are weak and poorly established. 

Even in Australia wherecomplusory helmet laws were introduced 1991 (the first such laws for any country), there has been recent claims that the laws should be revoked. Two researchers from Sydney University claim the law does not work and should be changed. Their research showed that although there had been a drop in the number of head injuries since the laws were introduced in 1991, the use of helmets was not the main reason.

Strong Arguments For and Against Helmets

Discover all the arguments for and against making helmets compulsory for bicycles
Discover all the arguments for and against making helmets compulsory for bicycles. Source: Public Domain

The reason was probably due to general improvement in road safety from measures such as random breath testing. They claim that scrapping compulsory head gear use would improve health rates and reduce injury rates because the increased number of cyclists on the roads would increase motorist's awareness of bike riders and motorists would learn to avoid them.

Dr Rissel compared the ratio of arm injuries to head injuries for cyclists admitted to hospital between 1988 and 2008. He assumed the ratio should have changed if helmet use reduced head injury rates. But the study showed that most of the change in the rates of head injuries occurred before 1991, that is before the laws came into force.

Also the trend for declining head injury rates continued without any major change when the laws were introduced (See figures below). However, Dr Rissel said that head gear was a good idea for many cyclists, especially those riding longer distances, and particularly for children.

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[Update: As pointed out in the comment below, the Alex Voukelatos and Chris Rissel research has been found to contain many errors and cannot not be relied upon. In a later issue of the journal, the authors concede a number of mistakes and that their paper has serious arithmetic and data plotting errors. They apologised for the unintentional errors and any confusion that this may generate. However they said that they had obtained additional data from Victoria and Western Australia, which confirmed their original findings that general improvements in road safety were probably behind the decline in head injuries among cyclists. This saga highlights the contentious nature of the debate.

The issues associated with data trends and how they affect before and after comparisons are highlighted in the Figure shown below.]

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The researcher who was instrumental in the move to make helmets use cumpulsory in Australia, more than 20 years ago. has challenged these research findings. Professor Frank McDermott, former chair of the Victorian Road Trauma Committee stated any sort of repeal would be very detrimental. He stated that the claim that the number of bike-related head injuries had remained similar since 1991 was dubious. He also criticised the method using 'ratios'. The ratio of arm versus head injury can be changed by either, and the lack of change may simply be due to there being a higher number of arm injuries. There was no specific helmet wearing data, and the injury data only relates to patients admitted to hospital. He says there is a lot of research which supports the wearing of head gear. He conducted a study on 1,710 Melbourne and Geelong bicycle casualties. About a quarter of them were wearing helmets and the head injury frequency was reduced about 50 per cent.

Christian King from Brain Injury Centre, Australia, agrees. He says it would be "an absurdity" if the legislation were overturned, or even challenged and prevention is better than any cure.

So who is right when you look at the available evidence?

Head gear for cylists is designed to protect the skull in the event of a bicycle accident. These devices were developed to reduce head trauma and brain damage while minimizing other consequences such as interference with peripheral vision. There is a raging technical argument, with no agreement, on whether head gear is helpful in reducing injuries, and whether the advantages are outweighed by their disadvantages in discouraging bicycle use. The arguments for and against making head gear use compulsory are strongly and bitterly debated by various interest groups. These arguments are based on differing interpretations of the accessible study papers, and on differing assumptions and biases pushed by those for and against. Moving from an association between to variables to establish a cause and effect is always difficult.

Helmets have been compulsory for sports cylists for many years, which is a strong argument for making helmets compulsory for all cyclists
Helmets have been compulsory for sports cylists for many years, which is a strong argument for making helmets compulsory for all cyclists. Source: Public Domain

Helmets are Compulsory for Sport Cyclists

Historically, road cycle racing guidelines set by the sport's ruling body, Union Cycliste Internationale (UCI), did not require that protective head gear should be worn. The matter was left to personal preferences and localized traffic laws. Most of professional road racing cyclists chose not to wear helmets because of discomfort and the extra weight of the helmets.

The first major move by the UCI to apply compulsory head gear use occurred in 1991. This triggered powerful disagreement from the riders and led to a riders' strike, that forced the UCI to abandon the idea.

Voluntary helmet use in expert ranks increased a little in the 1990s, the turning point was the death of Kazakh Andrei Kivilevin in March 2003 . The helmet-less Kivilev hit the ground after a collision and died from a serious skull fracture.

The new compulsory head gear laws were implemented on May 5, 2003. Initially riders were allowed to remove their helmets during final climbs more than 5 kilometres long. Later modifications were made so that the use of protective head gear was mandatory at all times.

No investigations have been released that show whether helmets have reduced head injuries. However it has been shown that modern head gear can decrease the aerodynamic drag on a rider by about 2% over a rider with no gear, giving a competitive advantage, and most riders support their use.

Bike Helmet Laws around the World

Several Countries have revoked their compulsory Helmet Laws and many don't have them.

Bike helmet rules throughout the world
Bike helmet rules throughout the world. Source: Public Domain
How helmets use is associated with reduced mortalities for cyclists
How helmets use is associated with reduced mortalities for cyclists. Source: Public Domain

Arguments Against Laws for Compulsory Helmets

How making helmets compulsory reduces the number of people who cycle regularly
How making helmets compulsory reduces the number of people who cycle regularly. Source: Public Domain
Get your helmet - there are many great designs
Get your helmet - there are many great designs. Source: Public Domain
Helmets work for many
Helmets work for many. Source: Public Domain

The Evidence Against Making Helmets Compulsory

Data from New Zealand
Data from New Zealand. Source: Public Domain
Data from South Australia
Data from South Australia. Source: Public Domain
Data for Primary School students
Data for Primary School students. Source: Public Domain
Data for head injuries in Western Australia
Data for head injuries in Western Australia. Source: Public Domain
Data for New South Wales, Australia
Data for New South Wales, Australia. Source: Public Domain

Arguments FOR Compulsory Bike Helmets





Aussie Bird Scarer Helmet - Magpie Deterant
Aussie Bird Scarer Helmet - Magpie Deterant. Source: Public Domain
There are many innovative helmet designs
There are many innovative helmet designs. Source: Public Domain
Many helmet designs are very fashionable
Many helmet designs are very fashionable. Source: Public Domain
LED bike helmet for safety at night
LED bike helmet for safety at night. Source: Public Domain
A folding bike helmet design to make it convenient to carry a helmet
A folding bike helmet design to make it convenient to carry a helmet. Source: Public Domain
A full helmet design for bikes
A full helmet design for bikes. Source: Public Domain