Cycles of all sorts

Promotion and compulsion

Helmet use has increased significantly in many, but not most, jurisdictions since the 1980s, primarily because of helmet promotion and compulsion laws. The following countries have mandatory helmet laws, in at least one jurisdiction, for either minors only, or for all riders: Australia, Canada, Finland, Iceland, USA, and New Zealand. In the U.S. 21 states have mandatory helmet laws. An analysis of helmet laws in the British Medical Journal showed that these laws have failed to yield measurable reductions in head injuries. The major documented effect of helmet laws is to reduce cycle use.

Use of cycling helmets is supported by numerous groups including the United States American Medical Association and the American National Safety Council. According to the NSC, head injuries cause 85 percent of bicycling fatalities, although it is unclear whether this is markedly different than for all trauma fatalities.

It is plausible that if a rider chooses to use a helmet, and maintains their safe cycling habits, they should be moderately safer than if they chose not to wear a helmet, although risk compensation theory states that an intervention as obtrusive as a helmet will very likely affect riding practice at the subconscious level. Wearing and non-wearing are both, therefore, sound choices, supportable from the available evidence. A person refusing to ride without one probably overestimates either the risks of cycling or the protective effect of helmets.

Promotion of helmets is somewhat more problematic. Helmet promoters routinely make claims which manufacturers cannot, due to truth in advertising restrictions. Promotion campaigns are often supported and/or funded by manufacturers. Bell, one major helmet manufacturer, supports both helmet promotion and, through its Legislative Assistance Programme, laws. The major problem with helmet promotion, from the point of view of cycle activists, is that in order to present the idea of a "problem" to match the solution they present, promoters tend to overstate the dangers of cycling. Cycling is, according to the evidence, no more dangerous than being a pedestrian. In fact, helmet compulsion in cars would be far more effective at reducing injuries than on bicycles.

Some bicycle activists complain that focus on helmets diverts attention from other issues which are much more important for improving bicycle safety, such as training, roadcraft, and bicycle maintenance. Of 28 publicly funded cycle safety interventions listed in a report in 2002, 24 were helmet promotions. For context, one evaluation of the relative merits of different cycle safety interventions estimated that 27% of cyclist casualties could be prevented by various measures, of which just 1% could be achieved through a combination of bicycle engineering and helmet use.

Data from around the world shows that despite the optimistic claims for injury reduction made by their proponents, no helmet law currently in force has led to a measurable reduction in cyclist head injury rates. There are a number of plausible explanations for this:

• the studies on which the laws are founded mainly compare those who choose to wear helmets with those who do not; forcing a cyclist to wear a helmet will not make them behave like the kind of cyclist who wears one by choice

• helmets are not designed to withstand motor vehicle impacts, but these account for most serious and almost all fatal cyclist injuries

• governments do not tend to measure minor injury rates; any protective device would be expected to be much more effective against minor injuries, rapidly tailing off with severity - although a few studies do claim that cycle helmets are more effective against serious than against minor injuries, it is more likely that the efficacy figures cited in advance are against a type of injury which subsequent statistics will not measure

• helmet laws tend to deter cycling; the theory of safety in numbers asserts that cycling becomes safer the more people who do it.

Cycling as a dangerous activity

A further source of contention is the apparent arbitrariness of cycle helmet promotion and/or compulsion. Ordinary cycling is not demonstrably more dangerous than walking or driving, yet no country promotes helmets for either of these modes (although there was an experiment in Japan with walking helmets for children, which demonstrated no measurable benefit). Cycle helmet use correlates inversely with the level of cycling in a given country. Official zeal for cycle helmets is greatest where cycling is a minority activity.

Detailed analysis of hospital admissions data also fails to support the idea that cycling is unusually dangerous: a study in the UK found that the proportion of cyclist injuries which are head injuries is essentially the same as the proportion for pedestrians at 30.0% vs. 30.1%.

Overall, cycling is beneficial to health - the benefits outweigh the risks by up to 20:1. Critics assert that anything which jeopardises that benefit should be carefully weighed to ensure it is likely to achieve some meaningful benefit in turn. Thus far, no helmet law has been shown to do that.