CRAG

Cyclists Rights Action Group

A helmet saved my life!

May 5th, 2012

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This claim, so often repeated, justifies the helmet law in the eyes of many.

Is it true? Here are some stats on cycling death & serious injury for children in NSW, before and after the helmet law. In the 2 years after the introduction of the helmet law, cyclists death and serious injuries decreased by 39%. Hooray! This proves that helmet saved lives! That is what many government funded studies have claimed after looking after similar data.

Can this 39% decrease be fully attributed to helmets though? What if it was due to something else? Like what? Like a decrease in the number of cyclists. After the helmet law, the number of child cyclists in NSW decreased by 44%. So the 39% decrease in death & serious injuries can be explained by fewer cyclists.

The helmet law was introduced at the same time as other road safety measures, like a crackdown on speeding and drink driving. This would have benefited cyclists and pedestrians similarly. Pedestrians death and serious injuries decreased by 19% during this period.

The risk of death and serious injuries for cyclists, adjusted for the lower number of cyclists, increased by 3%. We would have expected a decrease of 19% without the helmet law, like for pedestrians.

Far from “saving lives”, it seems that the helmet law has made cycling more dangerous.

Hmm …..

Where are all those cyclists saved by their helmets? They are nowhere to be found when looking at the stats. We’ve got many people claiming a helmet saved their life, yet the risk of death and serious injury from cycling increased.

How can that be?

One possible explanation is that if the risk of of accidents increased after the helmet law. The risk of non-head injury increased by 50% for child cyclists in NSW. That indicates an increase in accidents. Why? The most common explanations include risk compensation and safety in numbers. According to well-tested empirical data, reducing cycling by 44% increases the risk of accidents by 41%, which is close to the observed increased of 50%. This is what is meant by “safety in numbers”: reducing the numbers makes cycling more dangerous, possibly because motorists are less used to cyclists.

But surely, despite the increase in accidents, helmets should have saved these people. Unfortunately it doesn’t look like they did. The risk of death & serious injury increased by 50%, the same as the increase in accidents. It looks like the helmets made little difference. It’s not that surprising, considering that the piece of polystyrene labelled a “helmet” is not designed to protect in a serious accident.

On one hand, we have plenty of anecdotes from people who claim that a helmet saved their lives. On the other hand, we have evidence of an increased risk of accident and death after the helmet law. Both cannot be true at the same time. Perhaps it would be more accurate to say that some people BELIEVE that a helmet saved them. It’s natural to believe that, as it justifies wearing a helmet, and fits with the misleading advertising exaggerating the protection provided by helmets.

However that doesn’t mean that it is true. We don’t know what would have happened without a helmet. Most bicycle accidents do not result in serious head injuries, with or without a helmet. Helmet wearers forget that, and eagerly attribute their lack of head injury to their helmets, while in most cases the outcome would have the same without one. It is important to be realistic about helmets capabilities, and to base that assessment on facts rather than personal experiences, however traumatic and horrific they may be.

While so many people are eager to believe that a helmet saved them, few consider that the lack of a helmet could make them ride more cautiously, and have fewer accidents.

Before claiming that a helmet saved your life, it may be worth asking a few questions:

How do you know what would have happen without a helmet?
Would this accident have occurred without a helmet? Would you have ridden more cautiously?
Can a piece of polystyrene really save you in a serious accident?
Is it worth having a helmet law that reduce the number of cyclists, and increases the risk of accidents by 50%, for the “protection” provided by a piece of polystyrene?

Trying to cover up the risk that helmets can aggravate serious brain injury

March 31st, 2012

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Scientific research on brain injury reports that most brain injury is caused by rotational acceleration. Rotational acceleration means the head turning quickly. This quick rotation can create shearing inside the brain, tearing apart brain tissue and severing critical neural connections. This severe brain injury is called diffuse axonal injury. It can lead to permanent disability, when people have trouble operating normally, like in a vegetative state. This article provides a brief description of this from the doctors perspective.

Rotational acceleration is different from linear acceleration, which occurs when a moving object hits an obstacle, like a ball hitting the ground. Helmets are designed to protect against low levels of linear acceleration, for impacts below 20 km/h. However, they are not designed to protect against rotational acceleration.

Unfortunately, helmets can increase rotational acceleration. A study reports that soft-shell helmets grab the road, then cause rotational acceleration much higher than the tolerable maximum. On impact, the larger head volume amplifies rotational acceleration. Helmets can cause brain injury, or aggravate it. A study found that a difference of just 3cm in helmet circumference increases rotational acceleration by 150%. The difference between a helmeted and non-helmeted head is about 20cm.

This risk has been reported by other studies, including this study for the Australian government in 1987 (before the helmet law).

This risk is not easy to isolate in real life, as there are often other contributing factors. However, anecdotal evidence from a doctor reports that helmets convert what would have been focal head injuries into much more debilitating brain injuries. This is consistent with Canadian data that shows the length of stay in hospital increased following helmet laws, from 4.3 days to 6.9 days, suggesting more severe head injuries. In addition, the number of serious head injury admissions increased by 46% from 2000-2001 to 2003-2004.

After the introduction of the helmet law in NSW (Australia), the risk of death & serious injuries for child cyclists increased by 50%. Some of that could be due to “safety in numbers” and “risk compensation”. However it is also possible that some of it is due to increased rotational acceleration.

Ironically, bicycle helmets were imposed by claiming that they would prevent serious brain injuries, while actually they are more likely to aggravate serious brain injury. This awful mistake is embarrassing for people who have pushed for a helmet law without paying attention to negative side-effects. Making mandatory a device that can increase serious brain injury can have serious implications, both in terms of liability and loss of confidence in government policy. If the helmet law had to go through the medical process of checking for negative side-effects, it would not have been approved.

The Australian government introduced a policy of mandatory helmets despite being warned of this risk by its own researchers. Since then, the Australian government has not only failed to warn the public of this risk of serious brain injury, but also made false claims like “helmets save lives”, despite having no supporting evidence.

Many people have written to the government about the helmet law, mentioning the risk of brain injury from rotational acceleration. Suddenly, the government had an answer to this concern, claiming: “A 2009 study by the University of NSW confirmed the effectiveness of a bicycle helmet in reducing angular acceleration and subsequent brain injury in crashes”.

This study was not published in any scientific journal and could not be found anywhere. After much insistence, a copy was obtained from the RTA (a government agency). This study was mainly funded by the Australian government. The abstract states that the study’s aim is to “investigate the ability of a bicycle helmet to reduce angular head acceleration“. It seems to be a “study” with a pre-determined conclusion, like this one.

The study was set with unrealistic conditions, by using a hard-shell helmet at low speeds on a non-abrasive surface. Note that other studies have reported high rotational acceleration with soft-shell helmets, at speeds above 30 km/h, on a standard road surface. The study set up avoids theses known risks.

The study used a helmet with a ABS shell, like the one shown on the right, then magically generalised its results to all bicycle helmets, including the soft-shell helmet shown on the left, the most common bicycle helmet today. How can the “researchers” make such a fundamental mistake?

The study conclusion makes no mention of the unrealistically low speeds (5 km/h to 11 km/h) chosen for the study. How can any serious accident protection research only do tests a low speed? It is well known that speed is a major factor affecting the severity of an impact. Testing only a low, unrealistic speeds is almost useless.

The conclusion also fails to qualify the results by mentioning it was not using a realistic road surface. The flat surface used minimised the risk of the helmet sticking to the surface on impact. On a road, it is more likely the helmet would have stuck to the road and generated high rotational acceleration, as reported by other studies.

Despite the unrealistic conditions, the study results are generalized without qualifications or justification. The study claims that ”At worst bicycle helmets do not appear to exacerbate head injury risks arising from angular acceleration“. This is deceitful, as this “conclusion” is the result of the peculiar set up of the study, that cannot be generalised beyond the laboratory rather unusual conditions.

Is this research or is this disinformation? This study still hasn’t been published in a scientific journal, escaping scrutiny from independent researchers. Its only purpose seems to be to defend government policy. This is a poor attempt to cover up the risk that helmets can aggravate serious brain injury.

The government is expected to fund research that can lead to helmets providing better protection against brain injury, like it did in 1987 (before the helmet law). Commissioning research to cover up the deficiencies of government policy is fraud. If a private company was caught commissioning fake research to cover up the deficiencies of a product it mandates, there would be an outrage, with the government punishing the company with heavy fines and possibly a criminal conviction.

When it is the government conducting such fraud, who is there to keep them honest?

Challenging a helmet fine through the courts

March 24th, 2012

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A fine for not wearing a helmet in New South Wales (NSW), Australia, can be challenged in court. Sue Abbott successfully fought her helmet conviction in August 2010, arguing that wearing a helmet was more dangerous than not wearing one, and thus her actions were protected by a NSW state statute that says people are not compelled to follow laws when doing so would put their lives in danger. It is called the defence of necessity.

This newspaper article describes this successful challenge to a helmet fine.

The defence of necessity allows a crime to be excused if you have a reasonable belief that following the law would put your life or health at risk.

The test for this has 3 main parts:

1. You must have an honest belief that complying with the law puts you at increased risk of death or injury

For example:

I don’t wear a helmet because it increases the risk of serious brain injury.
Helmets are not designed to protect against serious brain injury, and can make it worse from:

Increasing the risk of accidents, as motorists have been shown to be less careful around helmeted cyclists, and helmeted riders tend to ride less cautiously.
Higher chance of head hitting road from larger head size
Soft shell helmets tend to grab the road surface & increase rotational acceleration, the main cause of serious brain injury.

There is plenty research backing up theses arguments, some of it mentioned in this website, in here for example. Generally, you can’t quote research in a court case unless the author of the research is there to support it. However, the defence of necessity merely requires that you hold a belief on reasonable grounds. The peer-reviewed research pointing the dangers of bicycle helmets provide sufficient reasonable ground.

It may also worth mentioning the position of the District Court Judge Ellis who, after carefully examining the evidence, who concluded that ”I frankly don’t think there is anything advantageous and there may well be a disadvantage in situations to have a helmet – and it seems to me that it’s one of those areas where it ought to be a matter of choice.”

2. It was necessary to do the activity that led to the breach (ie., to cycle)

This is a personal thing, so you need to emphasize what’s relevant to you. For example combining regular exercise with transport considering a busy work and family life is a necessity to stay in good health.

3. You must show that no harm was caused by breaking the law.

No harm was caused from riding on that specific occasion. Instead, cycling provides health benefits as well as reducing traffic congestion and pollution. Wearing a hat instead of a helmet reduces the risk of skin cancer.

More details from Sue Abbott court case can be found here.

There has been several other successful court challenges using the defence of necessity. Since then, Sue Abbott has successfully challenged a few more helmet fines for herself and for her daughter.

Another person successfully challenged several helmet tickets. In May 2011, Dan successfully challenged a helmet fine in court. His defence can be found here, while a description of his court appearance can be found here.

He got more fines later. He fought four helmet fines in another court case in November 2011. The magistrate recognised the validity of his defence, and let him off with a token fine. Sue Abbott was there supporting him, describing the trial here.

There is a pattern there. It is feasible to challenge a helmet fine in court, but you need to be well prepared.

The emergence of policy-driven studies

March 18th, 2012

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Generally, research is conducted with scientific discipline, with a purpose to further scientific knowledge. However, sometimes the entity funding the research has a vested interest in a certain outcome, compromising the independence of the research.

This has been the case for some research funded by drug companies for example, where the research results are used to sell or promote drugs. Powerful government and corporate interests are increasingly influencing scientific research through controlling its funding, as reported by Brian Martin from the University of Wollongong.

Government is a large source of research funding. By the mid 1990′s , evidence emerged that the bicycle helmet law had been a failure. The Australian government started funding “studies” defending this new government policy. Such policy-driven studies have been then used to obfuscate the failure of the helmet law.

In 1995, the government commissioned a policy-driven study that became known as the Henderson Report. Written in an authoritative style, it pretends to be scientific. That illusion breaks down when one notices two unusual features for a scientific report:

It contains many strongly worded, unqualified assertions. Researchers with scientific integrity tend to be very careful with their assertions, making sure they are backed up by sufficient evidence and qualified by their context. You rarely see unsupported or unqualified assertions in a scientific report.
Assertions are not annotated, making it impossible to verify the data source.

This is not a scientific report. It is unsubstantiated opinions presented as facts. Here are a few of them (From the Executive Summary, under “The effectiveness of head protection”):

“Helmet design and construction is based on known mechanism of head and brain injury”. Not true. This ignores rotational acceleration, the main cause of brain injury.
“At the very minimum helmets halves the risk of head injury”. Not true. Helmets can aggravate brain injury through rotational acceleration.
“Those who do not wear helmets are several times more likely to sustain injury to the brain tissue”. Not true. Ignores that helmet wearers are more likely to have accidents.
“in Victoria, the number of bicyclists with head injuries decreased by 48 per cent”. Misleading. Ignores the decline in cycling and head injury reduction for pedestrians.
“The vast majority of head impacts occurring … are easily survivable if a Standards-approved helmet is worn”. Not true. Helmets are not designed to protect in a serious accident.
“No studies have come to conclusions contrary to the above”. Not true. The Hillman report, one of the most comprehensive and famous review of helmet research at the time, is completely ignored.

Many assertions in this report are false or misleading. Surprisingly, the author mentions motorcycle helmets, as if they were comparable. This “study” has received much criticism, notably in the vehicular cyclist and here.

Despite data showing that cycling safety has lagged pedestrian safety since the helmet law, policy-driven studies found a way to claim that the helmet law was a success. For example, a 1997 report from a government agency made two misleading claims:

Cycling casualties decreased after the helmet law. This ignored the decrease in the cycling. Per cyclists, cycling casualties increased.
A ‘strong correlation’ between higher helmet wearing rates and lower casualties. The underlying data indicates the opposite.

Most medical case-studies or government-funded reports like this one, claiming that the helmet law has been effective, make similar errors. They ignore the decline in cycling. They attribute all apparent safety improvements to helmets, failing to consider confounding factors, like significant road safety improvements occurring at the same time resulting in a decrease in head injuries for pedestrians. These are odd “mistakes” from professionals who have a duty to do due diligence in their research, making sure their claims is backed by solid data.

In 2000, the Australian Transport Safety Bureau (ATSB), a government agency, released a meta-analysis, that claims to provide overwhelming evidence that bicycle helmets reduce the risk of brain injury. This claim was rebutted in 2003, highlighting a lack of understanding of brain injury. The ATSB did not reply to the rebuttal, thus giving up on its claim. Despite being discredited, this analysis is still used by the government to defend the helmet law, claiming that helmets reduce the risk of head injury by 60%.

In 2011, a meta-analysis re-assessed this ATSB meta-analysis. It concluded: “This paper shows that the meta-analysis of bicycle helmet efficacy … was influenced by publication bias and time-trend bias that was not controlled for. As a result, the analysis reported inflated estimates of the effects of bicycle helmets“. Publication bias is the tendency of contradictory or inconclusive results not to be published, resulting in a literature formed of apparently consistent findings that exaggerate the actual effect.

Since then, various government agencies have kept throwing more taxpayers money at misleading policy-driven “studies”, attempting to obfuscate the failure of the helmet law.

A university seems to be moving away from policy-driven studies, as reported here: “the faculty wished to move away from conducting sponsored policy studies for government because this did not generate valuable intellectual property“

Independent researchers who have studied the result of the helmet law have come to different conclusions.

Dorothy Robinson, a researcher from the University of Armidale, said “[the] governments [who introduced the helmet laws] do not like to admit they’ve made mistakes”.

Bill Curnow, a retired scientist from the CSIRO, wrote as a conclusion in a scientific article: “Compulsion to wear a bicycle helmet is detrimental to public health in Australia but, to maintain the status quo, authorities have obfuscated evidence that shows this.”

An independent group of public health and transport practitioners and researchers wrote in their report: “The failure of mass helmet use to affect serious head injuries, be it in falls or collisions, has been ignored by the medical world, by civil servants, by the media, and by cyclists themselves. A collective willingness to believe appears to explain why the population-level studies are so little appreciated. …. The disconnect between received wisdom and the facts is stark.“

These are strong words from independent researchers, revealing frustration at the government unwillingness to admit they made a mistake.

For how long can policy-driven studies sustain failed policies?

In what way can this be justified as good use of taxpayers money?

Research on helmet law in the UK

February 26th, 2012

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In the UK, the helmet law has been debated for a long time, with the usual set of emotional arguments from helmet believers. So far, rationality has prevailed, thanks to the efforts of the Cyclists Touring Club and independent researchers. Here is some of the research that has help sanity prevail.

The Hillman report, one of the most comprehensive early research done in 1992. It was ahead of its time. Much of what was described in the conclusion subsequently happened in Australia and New Zealand.

The insightful conclusions for the report include:

“By wearing helmets, cyclists are at best only marginally reducing their chances of being fatally or seriously injured in a collision with a motor vehicle which is the predominant cause of these injuries. Even the most expensive ones provide little protection in these circumstances. Moreover, the argument in favour of helmets would have validity if there were proof that behaviour does not change in response to perceived risk. But there is no such proof. Safety devices encourage higher levels of risk-taking. As a result, cyclists are likely to ride less cautiously when wearing a helmet owing to their feeling of increased security. After all, the message of the advocates of helmet wearing is that such a practice will protect the cyclist’s head adequately in the event of any accident, not just a minor one when cyclists are hit by very slow-moving vehicles or fall off and hit their heads on the ground. Cyclists may be less likely to have an accident if they are not wearing a helmet, and are therefore riding with greater care owing to an enhanced sense of their vulnerability.

Furthermore, people are discouraged from cycling if their perception is heightened that it is a ‘dangerous’ form of travel and that it is only safe to do so if a helmet is worn. The result of this is that the considerable latent demand for cycling – an ideal mode for the majority of the population for most of their journeys – continues to be suppressed. As cycling is also a convenient and routine way of maintaining fitness, a significant route to public health is prejudiced.

There remain then three questions to be answered. First, should helmet wearing be made mandatory? The report on which this paper is based has revealed no case for such a law. In addition to the absence of proof that helmet wearing reduces the risk of head injury, such a law would represent an infringement of civil rights. Moreover, where it has been introduced, it has led to a significant reduction in cycling.

The second question to address is whether, whilst not making it mandatory, cyclists should nevertheless be encouraged to wear helmets -in effect, obliged to do so by ‘moral’ persuasion rather than by law. However, other than concern on the civil rights issue, the approach to helmet wearing by this means rather than by coercion through legislation would appear to be equally invalid.

This then leads to the third question concerned with alternative and effective ways of reducing the risk of accidents, and therefore of head injury, among cyclists. The primary means of reducing serious head injury among cyclists is to create an environment in which accidents are less likely to occur. Such a strategy based on tackling the source of accidents in which cyclists are involved has far greater scope for reducing head injuries than the questionable benefits of promoting helmet wearing among cyclists.“

The 2005 report form the National Children Bureau focused on cycling safety, not just cycling helmets. The section on bicycle helmets, written by an experienced cyclist who regularly wears a helmet, concludes:

“The conclusion from the arguments outlined above is that the case for cycle helmets is far from, sound. The strong claims of injury reduction made by helmet proponents have not been borne out for fatalities (which this paper argues is the most methodologically sound test of effectiveness) in real-life settings with large populations. …

the benefits of helmets need further investigation before even a policy supporting promotion can be unequivocally supported. ….

The cycle helmet debate shows the dramatic power of real life events in shaping our understanding of causality. Tragedies happen; child cyclists are killed or left disabled for life; and we cannot let go of the belief that something
could and should have been done to stop that particular event from happening – especially when that something is so simple as wearing a helmet. We find it hard to accept that the helmet may have made no difference. We find it harder to accept that encouraging or forcing children to wear helmets might also encourage them to ride in a more dangerous way and paradoxically to increase the risk that they will suffer an accident. And we find it much harder to accept that compulsory helmet use might put children off cycling altogether, leaving them less physically active, and – many years later – more likely to die of heart disease. Think of all the uncertainty behind that line of argument, compared with the seeming rock-solid conviction that a helmet could have saved that particular child’s life, at that particular time. And of course the fact that we are talking about children, who have a claim on our protection and who are still getting to grips with the world, makes it so much more difficult to accept the limitations on our ability to prevent them coming to harm. We cannot ignore the human suffering, pain and loss that lie behind the research and statistics. But our response to it demands reflection and perspective as well as sympathy and conviction.“

In 2011, the Transport and Health Study group, an independent British society of public health and transport practitioners and researchers, released Health on the Move 2, a book aimed to be “a clear and comprehensive account of what would constitute a healthy transport system.” The section on bicycle helmets evidence, approaches the topic of the helmet law from a health perspective. It includes a summary of the research on the helmet law.

The report is written in a neutral tone, yet you can sense the frustration of the researchers here: “The failure of mass helmet use to affect serious head injuries, be it in falls or collisions, has been ignored by the medical world, by civil servants, by the media, and by cyclists themselves. A collective willingness to believe appears to explain why the population-level studies are so little appreciated.”

The report conclusions include:

“The disconnect between received wisdom and the facts is stark.

The facts are:

2. There is however a disturbing discrepancy between engineering or clinical evidence of the effectiveness of helmet wearing (which suggest them to be effective) and population studies (which suggest that they are not).
3. Plausible explanations of this discrepancy include cyclists taking greater risks because they think their helmet makes them safe or drivers taking less care of helmeted cyclists because they see them as less vulnerable. A single study has examined this but its findings supports the latter of these.

5. It is now well established that legislation mandating cycle helmet use causes a reduction in the levels of cycling and thereby does more harm than good.
6 It is unclear whether this is because many people find cycle helmets troublesome, because many people find them unfashionable and odd or because people consider the mandation of helmet use as evidence that cycling is dangerous.”

Helmet believers doubtful after increase in injuries

February 18th, 2012

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Helmet believers do not like to admit that the helmet law was a mistake. A helmet believer from Canada researched this topic and reports a decrease in cycling and an increase in the risk of injury in provinces of Canada where a helmet law has been introduced.

Same result in the US. Alongside a rise in helmet wearing, cycling decreased and the rate of head injury increased by 51%. Risk compensation is mentioned as the most likely cause of the rise in injuries.

A recent study in New Zealand found the same result: a decrease in cycling and an increase in the risk of accident and injury. Cyclists injuries more than doubled compared with pedestrians

Same result in Australia: a decrease cycling, an increase in the risk of accidents by 50%, and an increase in the risk of deaths & serious injuries by 50%.

This large increase in accidents observed after introducing a helmet law is a serious concern for policy makers. Can this rise in accidents be compensated by a piece of polystyrene called a helmet? It doesn’t look like it, as the rise in injuries indicates. Even the risk of head injuries has risen.

Do helmets really protect racing cyclists?

January 26th, 2012

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Most sport cyclists wear their helmets as it is “obvious” that they protect them. But do they really?

Since helmets have been made mandatory for racing cyclists, deaths of professional cyclists while racing have doubled. So where is the protection provided by helmets?

It is odd that helmets are imposed on racing cyclists as they travel at speeds far greater than what these polystyrene helmets are designed to handle.

Helmets have brought a new stream of sponsorship income for professional cycling. Who has it benefited besides helmets manufacturers?

This result of increased deaths after widespread helmet use is consistent with what was observed after the helmet law in Australia, where a 50% increase in accidents, death & serious injuries was reported for child cyclists in NSW.

Do helmets provide sufficient protection to compensate for the increased risk of accidents? The evidence so far is that they don’t.

Are bicycle helmets dangerous?

December 12th, 2011

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Politicians claim that “Helmets save lives”.

Is this true? CRAG has asked for evidence, but the Australian government has been unable to provide convincing evidence. This is not surprising, as there is actually contrary evidence, showing that the risk of death and serious injury increased by 50% for child cyclists in NSW after the helmet law.

Bicycle helmets increase risks in several ways:

1. Increased risk of having an accident, through risk compensation. Risk compensation is a well-known safety phenomenon that has been confirmed for children and for cyclists in this research that reports that helmeted cyclists tend to compensate by riding faster. Helmets seem to affect motorist behavior as well, with research showing that motorists drive closer to helmeted riders and are more likely to hit them. After the helmet law, the risk of non-head injuries increased by 50% for child cyclists in NSW, indicating a significant increase in the risk of accidents.

2. In the event of an accident, increased risk of the head hitting the road. Helmets increase the volume/size of contact area of the head. This study reports that helmeted riders are more than twice as likely to hit their head in an accident, with the additional impacts being to the sides. This is consistent with post-crash studies that found that most helmets show impacts to the side, areas where a bare head may not have been hit. A 1988 study found that helmeted riders report hitting their heads seven times more often than un-helmeted riders. A bare head, often protected by the shoulders, provides the lowest risk of head contact in the event of an accident.

3. The standard bicycle helmet is not adequate for children more flexible heads. Research reports that bicycle helmets are too stiff for children’s more deformable head, calling for a different standard for children’s helmets.

4. The design of current bicycle helmets is based on an obsolete theory that believed that brain injury was due to linear acceleration (i.e. hitting your head against a wall). More recent research has shown that the main cause of severe brain injury is rotational acceleration (i.e. head turning quickly). Helmets cannot protect against it but they can increase it. Soft-shell helmets grab the road surface, and then cause rotational acceleration much higher than the tolerable maximum. On impact, the larger head volume amplifies rotational acceleration. A study found that a difference of just 3cm in helmet circumference increases rotational acceleration by 150%, potentially aggravating brain injury. The difference between a helmeted and non-helmeted head is about 20cm. Helmets can cause brain injury, or aggravate it.

5. There is anecdotal evidence that helmets convert what would have been focal head injuries into much more debilitating brain injuries. This is consistent with Canadian data that shows the length of stay in hospital increased following helmet laws, from 4.3 days to 6.9 days, suggesting more severe head injuries. In addition, the number of serious head injury admissions increased by 46% from 2000-2001 to 2003-2004.

Bicycle helmets are a safety trade-off. They can reduce focal skull injuries from linear acceleration in minor accidents. However, they increase the chance of the head hitting on impact, particularly side impacts that generate high rotational acceleration, potentially aggravating brain injury. A soft-shell helmet tends to disintegrates on impact, absorbing little energy. This crumbling is what ironically many people mistake the helmet for as having saved their life.

A recent meta-analysis of helmets effectiveness reports that there seems to be no net beneficial effect overall from soft-shell helmets. They protect against skull injuries in low-speed accidents, but do not protect against facial injuries, and increase the risk of neck injuries.

It is not safe to assume that the padding provided by helmets outweighs the increased risk of accidents, and the risk of aggravating neck and brain injuries. The belief that helmets can only improve safety may be a myth. While a helmet might protect IF you have an accident AND it is at low speed AND you fall on your head, is it really worth the increased risk of having a serious accident?

Bicycle helmets impact on injuries

Reducing Injuries	Increasing Injuries
In minor accidents, a helmet can spread the load and reduce the severity of skull injuries if the cyclist falls on their head	Increased risk of accidents Increased risk of head impact Increased risk of neck injury Increased risk of brain injury

We do not know whether helmets provide a net safety benefit. What we do know is that cycling has become more dangerous after the helmet law, by increasing accidents and injuries by 50% for child cyclists in NSW. Some of this degradation in safety was due to a reverse “safety in numbers” effect, that is not inherent to helmets. However, it is possible that some of this degradation in safety was due to the helmet itself, either through risk compensation, increased rotational acceleration, increased risk of the head hitting the road, or too stiff helmets inadequate for children heads.

The UK’s National Children’s Bureau provided a detailed review of cycling and helmets in 2005, stating that the case for helmets is far from sound and the benefits of helmets need further investigation before even a policy supporting promotion can be unequivocally supported.

This dilemma about the trade-off between protection in minor accidents vs. risk of brain injury is what enabled an Australian cyclist to successfully challenge a helmet fine on the basis that wearing a helmet could be dangerous. The judge agreed that the helmet could be dangerous in some circumstances, and that wearing a helmet ought to be a matter of choice.

When reasonable doubt exists about any product providing a net benefit, people should have the right to choose.

This seems hard to believe, as there have been many studies that claim that helmets protect against 60% or 80% of brain or head injuries. However, most of these studies lack scientific discipline. Like this one, many of those studies started from a preconception that helmets worked and attempted to “prove” it. This is hardly scientific research. Many of those studies were funded by the helmet industry or by the Australian government, who have a vested interest in exaggerating the benefits of helmets.

Many of the studies exaggerating the benefits of helmets make physically impossible claims.

How can a helmet reduce 80% of head injuries considering they don’t cover the face where 70% of head injuries are?

How can a helmet reduce 80% of brain injuries considering they cannot protect against the main cause of brain injury, rotational acceleration, and they can increase rotational acceleration?

How can these studies make such physically impossible claims? Like this study, many of these studies fail to consider confounding factors, a common error in statistics. They reach unwarranted conclusions far too eagerly. Other examples of misleading research can be found here.

In 2000, the Australian Transport Safety Bureau (ATSB), a government agency, released a meta-analysis, that claims to provide overwhelming evidence that bicycle helmets reduce the risk of brain injury. This claim was rebutted in 2003, highlighting a lack of understanding of brain injury. The ATSB did not reply to the rebuttal, thus giving up on its claim. Despite being discredited, this analysis is still used by the government to defend the helmet law, claiming that helmets reduce the risk of head injury by 60%. How can a device whose mass adoption has led to an increase in the risk of head injuries still be claimed to reduce the risk of head injuries by 60%? Such propaganda disregards the risks of helmets while exaggerating their benefits, ignoring the real-world consequences of adopting helmets.

In 2011, a meta-analysis re-assessed this ATSB meta-analysis. It concluded: “This paper shows that the meta-analysis of bicycle helmet efficacy … was influenced by publication bias and time-trend bias that was not controlled for. As a result, the analysis reported inflated estimates of the effects of bicycle helmets“. Publication bias is the tendency of contradictory or inconclusive results not to be published, resulting in a literature formed of apparently consistent findings that exaggerate the actual effect.

How can such misleading “studies” be justified as a form of public service?

Such deceptive studies add little to scientific knowledge. They exaggerate the reduction of the risk of minor injuries while ignoring the increased risk of serious injuries. This tends to mislead policy makers towards false “solutions” to cycling safety, while neglecting more effective measures like rider training and improving the behavior of motorists towards cyclists. This might explain why Australia has one of the worst cycling safety record among developed countries (ref page 43).

Has the helmet law improved safety?

December 7th, 2011

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The helmet law has been introduced on a BELIEF that it would improve safety. The assumption was that, since helmets provide some protection, forcing everybody to wear a helmet can only improve safety.

Has it improved safety? There has been surprisingly little comprehensive research to assess the effectiveness of the helmet law, or to compare cycling safety in Australia with the rest of the of the world.

A noticeable impact of the helmet law has been to reduce cycling. Far more people stopped cycling rather than opted to wear a helmet.

The helmet law was introduced in Australia at the same time as other road safety measures like a crackdown on speeding and drink driving. A way to isolate the impact of the helmet law from these other safety measures is to compare cycling safety with pedestrian safety.

Some government funded studies like this one claim that the helmet law has been effective. Such “studies” fail to take into account two important factors:

There were 30 to 40% fewer cyclists. The risk must be adjusted per km cycled or per cyclist.
Head injuries also declined for pedestrians. Other road safety improvements must be taken into account.

Those studies attribute all apparent safety improvements to helmets, failing to consider confounding factors. After adjusting for those factors, the touted decline in head injuries vanishes.

An objective assessment of the effectiveness of the helmet laws needs to take into account the decline in cycling and the impact of other safety measures introduced at the same time.

Dr. Dorothy Robinson has done thorough research in this area. In this article, she mentions that the helmet law has increased the risk of injury per cyclist. A short summary of Dr. Robinson’s work in this area can be found here.

Cycling injuries has shown a similar trend as pedestrian injuries after the helmet law. The large rise in helmet wearing does not seem to have made much difference. Taking into account the decline in cycling by 30 to 40%, the risk of injury per cyclist increased.

A more detailed analysis can be found in this report (page 465). After the helmet law, the risk of death and serious injuries for child cyclists increased by 21%, compared to a decrease by 21% for child pedestrians.

From the graph above, you can see how a biased study can claim that the helmet law has improved safety, by focusing on the apparent decline in injuries, while ignoring that the number of cyclists declined even further, and ignoring that pedestrians benefited from significant safety improvements as well.

This data indicates that the risk of death & serious injury for child cyclists in NSW increased significantly (by 50%) compared to what would have been expected without the helmet law. Explanations for the deterioration in safety include risk compensation and safety in numbers, resulting in an increase in accidents. By reducing the number of cyclists, the helmet law has contributed to make cycling more dangerous.

Evidence of an increase in accidents can be seen in Table 2 on Page 465 of the report. Hospital data reveals an increase in risk of non-head injuries by 51%, indicating an increase in risk of accidents of about 50%.

Cycling has become more dangerous after the helmet law. It is unlikely that a large increase in the risk of accident can be compensated by a piece of polystyrene. It is misguided to insist on reducing the risk of minor injuries when it increases the risk of serious injuries in other ways.

Australia has one of the worst cycling safety record among developed countries (ref page 43). Not surprising considering it has one of the lowest level of cycling participation.

New Zealand introduced a bicycle helmet law in 1994. A cycling safety perception survey reveals that most people believe that cycling has become more dangerous since the helmet law. Comparing cycling with ‘when I was at high school’ (before the helmet law), 83% report that cycling is more dangerous, while only 20% believe that cycling has become safer over the last 10 years (since 1994: introduction of helmet law).

This is consistent with the largest ever cycling casualty study, involving over 8 million cases of injury and death to cyclists over 15 years in the USA, concluded: “There is no evidence that hard shell helmets have reduced the head injury and fatality rates. The most surprising finding is that the bicycle-related fatality rate is positively and significantly correlated with increased helmet use.” Rodgers, G.B., Reducing bicycle accidents: a reevaluation of the impacts of the CPSC bicycle standard and helmet use, Journal of Products Liability, 11, pp. 307-317, 1988

Misguided study affected by confirmation bias

November 20th, 2011

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Some helmet studies seem affected by confirmation bias, with a lack of scientific discipline. One example is this study, described in this newspaper article.

The study states it is designed to “demonstrate the safety benefits of helmet use“. It seems that the researchers assume that helmets are effective and attempt to prove it. This is not scientific approach, it is more like an attempt to prove a preconception. With such an approach, there is a strong tendency for confirmation bias: data that does not lead to the preconception tends to get ignored.

The bias is revealed in the article mentioned above.

“But the percentage of injured cyclists who needed treatment for serious head injuries dropped from 10.3 per cent in 2005 to 2.5 per cent last year.”That could be put that down to helmet use,” ”

What is odd about this conclusion is that helmet usage in the area was lower in 2009 than in 2005. Lower helmet usage was correlated with lower head injuries. How can lower head injuries can be credited to helmets when fewer people were wearing helmets?

From the study report, unhelmeted cyclists had an Injury Severity Score (ISS) of 7, much higher than helmeted cyclists with an ISS of 4. ISS reflect all injuries, not just head injuries (25% of injuries). A higher ISS indicates more severe accidents. Any apparent difference in head injuries cannot be fully attributed to helmets, accident severity is another key factor. This is a common error is statistical analysis, a lack of checking for confounding variables. This is a fundamental flaw is this study that renders its conclusions invalid. Yet the study concludes:

“The study confirmed the utility of helmet use in preventing serious head injury after cycling accidents. This was the only factor in this study to influence the severity of injury.”

This is an odd claim considering the large difference in accident severity. How can the researchers have missed accident severity as a relevant factor? This oversight shows a disturbing lack of scientific discipline.

Despite the lack of scientific discipline, the bias of the researchers, and the flaws in the study, the government claims that this “confirms” that helmets are effective. Such claims are misleading and deceptive. Either the government is unable to identify flawed research, or it is being disingenuous.

This is unfortunately typical of many “studies” done within the medical industry, where the researchers are focused on proving a preconception, rather on trying to better understand the effectiveness of helmets. While these studies may be well meaning, they are misleading. This can mislead people towards false “solutions” to cycling safety, while giving a false sense of safety and neglecting more effective measures.