A bicycle helmet is designed to attenuate impacts to the head of a cyclist in falls while minimizing side effects such as interference with peripheral vision. There is ongoing scientific research into the degree of protection offered by bicycle helmets in the event of an accident, and on the effects of helmet wearing on cyclist and motor vehicle driver behaviour.
There is active debate over what can be concluded from available studies, and on whether the use of helmets by cyclists should be promoted or mandated, either just for children, or for cyclists of all ages. In particular the debate over bicycle helmet laws is intense and occasionally bitter, often based not only on differing interpretations of the scientific and other academic literature, but also on differing assumptions and interests of various parties.
Cycling risk and head injury
In the USA, two-thirds of cyclists admitted to hospital have a head injury. Ninety percent of cyclist deaths are caused by collisions with motor vehicles. For cyclists admitted to hospital in Western Australia before the helmet law, about 30% of cyclists and 30% of pedestrians had head injuries. Trends and proportions of cyclists admitted to hospital with head injury were similar for all road users.
Many closed-head injuries can be prevented by proper use of safety equipment during dangerous activities. Common safety features that can reduce the likelihood of experiencing a brain injury include helmets, hard hats, car seats, and safety belts. Another safety precaution that can decrease a person’s risk for brain injury is not to drink and drive or allow oneself to be driven by a person who has been drinking or who is otherwise impaired.
Helmets can be used to decrease closed-head injuries acquired during athletic activities, and are considered necessary for sports such as American “tackle” football, where frequent head impacts are a normal part of the game. However, recent studies have questioned the effectiveness of even American football helmets, where the assumed protection of helmets promotes far more head impacts, a behavior known as risk compensation. The net result seems to have been an increase, not decrease, in TBI (Traumatic Brain Injury). The similar sports of Australian-rules football and rugby are always played helmetless, and see far fewer traumatic brain injuries.
Bicycle helmets are perhaps the most promoted variety of helmet, based on the assumption that cycling without a helmet is a dangerous activity, with a large risk of serious brain injury. However, available data clearly shows that to be false. Cycling (with approximately 700 American fatalities per year from all medical causes) is a very minor source of fatal traumatic brain injury, whose American total is approximately 52,000 per year. Similarly, bicycling causes only 3% of America’s non-fatal TBI.
Still, bicycle-helmet promotion campaigns are common, and many U.S jurisdictions have enacted mandatory bicycle-helmet laws for children. A few such jurisdictions, a few Canadian provinces, plus Australia and New Zealand mandate bicycle helmets even for adults. A bicycle-helmet educational campaign directed toward children claimed an increase in helmet use from 5.5% to 40.2% leading to a claimed decrease in bicycle-related head injuries by nearly 67%. However, other sources have shown that bicycle-helmet promotion reduces cycling, often with no per-cyclist reduction in TBI.
Estimates of bicycle-helmet use by American adults vary. One study found that only 25-30% of American adults wear helmets while riding bicycles, despite decades of promotion and despite sport cyclists’ adoption of helmets as part of their uniform. It would appear that the typical American adult correctly recognizes ordinary cycling as a very minor risk.
Following the commercial (as opposed to public-health) success of bicycle helmets, there have been successful attempts to promote the sale of ski helmets. Again, results have been less than impressive, with great increases in helmet use yielding no reduction in fatalities, and with most injury reduction confined to lacerations, contusions, and minor concussions, as opposed to more serious head injuries.
There have been rare campaigns for motoring helmets. Unfortunately, just as people greatly overestimate the TBI danger of bicycling, they greatly underestimate the risk of motoring, which remains the largest source of TBI in the developed world, despite the protective effects of seatbelts and airbags.
Video source: How It’s Made
Photo source: bellhelmets.com