Abstract
After the helmet law, many cyclists insisted that their helmets had saved them.
Yet cycling injuries tripled.
Why? Because helmets increase the risk of accidents.
What the data tells us
Here are some stats on cycling death & serious injury for children in NSW, before and after the helmet law. Two years after the introduction of the helmet law, death and serious injuries decreased by 32%. Hooray! This proves that helmet saved lives! That is what many government commissioned studies have claimed.
Can this 32% 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%. The decrease in death & serious injuries was less than the reduction in cycling.
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. Pedestrians death and serious injuries decreased by 23% during this period.
The risk of death and serious injuries for cyclists, adjusted for the lower number of cyclists, increased by 21%. For pedestrians it decreased by 21%.
It seems that the helmet law has made cycling more dangerous.
Hmm …..
Where are the cyclists saved by their helmets? They cannot be found in the injury data. Many people claim a helmet saved their life. Yet the risk of death and serious injury has increased.
Why have helmets failed to reduce injuries?
One possible explanation is that the risk of accident tripled.
A false sense of safety can induce people to take more risks, leading to more accidents and more injuries. This is risk compensation, a well-known safety factor:
“the law of unintended consequences is extraordinarily applicable when talking about safety innovations. Sometimes things intended to make us safer may not make any improvement at all to our overall safety”
“the rate of head injuries per active cyclist has increased 51 percent just as bicycle helmets have become widespread. …
the increased use of bike helmets may have had an unintended consequence: riders may feel an inflated sense of security and take more risks. …
The helmet he was wearing did not protect his neck; he was paralyzed from the neck down. …
”It didn’t cross my mind that this could happen,” said Philip, now 17. ”
I definitely felt safe. I wouldn’t do something like that without a helmet.” ”
Risk compensation also affects motorists who tend to be less careful around helmeted cyclists. As reported in a study published by the University of Bath in the UK:
“Bicyclists who wear protective helmets are more likely to be struck by passing vehicles”
Both the behaviour of helmeted cyclists and surrounding motorists increase the risk of accidents.
There is a well-known phenomenon called safety in numbers. According to empirical data, reducing cycling by 44% increases the risk of accidents by 41%. Research published in the Injury Prevention journal concluded:
“the behavior of motorists controls the likelihood of collisions with people walking and bicycling. It appears that motorists adjust their behavior in the presence of people walking and bicycling …
A motorist is less likely to collide with a person walking and bicycling if more people walk or bicycle. Policies that increase the numbers of people walking and bicycling appear to be an effective route to improving the safety of people walking and bicycling.”
What protection do helmets provide?
Despite the increase in accidents, helmets should have saved these people. Helmets saved some of them, as the 55% increase in the risk of death & serious injury is lower than the 93% increase in accidents. Yet overall the risk of death & serious injury increased.
Unfortunately polystyrene based helmets are not designed to protect in a serious accident:
“In cases of high impact, such as most crashes that involve a motor vehicle, the initial forces absorbed by a cycle helmet before breaking are only a small part of the total force and the protection provided by a helmet is likely to be minimal in this context. In cases where serious injury is likely, the impact energy potentials are commonly of a level that would overwhelm even Grand Prix motor racing helmets. Cycle helmets provide best protection in situations involving simple, low-speed falls with no other party involved. They are unlikely to offer adequate protection in life-threatening situations.“
Helmets make little difference in a serious accident, as Dr Hooper reports:
“Looking at evidence, it does not matter if people are wearing a helmet or not, any serious accident on a bike is likely to kill them,”
Suspending belief
On one hand, we have plenty of anecdotes from people who claim that a helmet saved their lives.
On the other hand, we have an increased risk of death and serious injury 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:
“The next time you see a broken helmet, suspend belief and do the most basic check – disregard the breakages and look to see if what’s left of the styrofoam has compressed. If it hasn’t, you can be reasonably sure that it hasn’t saved anyone’s life.“
A helmet protects by absorbing the energy of the impact through compressing the polystyrene layer. If the polystyrene has not compressed, but has broken into pieces instead, it has failed. It may have prevented bruises & lacerations, but it didn’t do much to reduce the energy of the impact.
One can expect a severe head injury from cycling once every 8,000 years of average cycling.
It is natural to assume a helmet saved us. But that doesn’t mean it is true. We don’t know what would have happened without it. Cyclists, with and without helmets, get hit by cars; the survival rates are identical. Most bicycle accidents do not result in serious head injuries, with or without helmets. We tend to overlook this, and attribute a lack of head injury to the helmet:
“see the double-standard of finding it entirely logical when helmeted cyclists who survive collisions report that wearing a helmet saved their life. It is a powerful emotional argument, but logically, statistically, and scientifically, it is erroneous for the same reasons it would be erroneous to say that not wearing a helmet saved Gene Hackman’s life. If a cyclist wears a helmet and they emerge from a collision alive, that implies correlation, not causation.”
It is important to be realistic about helmets capabilities, and to base that assessment on facts rather than personal experiences, however traumatic they may be.
After being asked
“Can your helmet save your life?”,
a helmet manufacturer salesperson shrugged and laughed uncomfortably, before responding:
“Can it?” “Well, not save your life, no.”
This doesn’t mean that it is not possible that a helmet saved a cyclist life. It might have in some cases. However, few people consider that the lack of a helmet tends to make them ride more cautiously, and have fewer accidents. If they weren’t wearing a helmet, they may not have had a crash in which their life needed saving in the first place.
In many other instances, a helmet failed to save cyclists. Overall the risk of death & serious injury increased after the helmet law.
Before claiming that a helmet saved your life, ask:
- How do I know what would have happen without a helmet?
- Would I have ridden more cautiously without a helmet?
- Is it reasonable to rely on a piece of polystyrene to save my life in a serious accident?