Cycle helmets: An overview of the evidence

from here

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THE UK’S NATIONAL CYCLISTS’ ORGANISATION

www.ctc.org.uk/campaignsbriefings.

Key points:

• Cycling is hugely beneficial to people’s health. Those who cycle regularly in mid-adulthood have a level of fitness equivalent to being 10 years younger, and have a life expectancy 10 years above the average.

• By contrast, the risks of cycling are not exceptionally high, and are very small relative to the health benefits. You are in fact less likely to be killed in a mile of cycling than a mile of walking. The Government estimates that the health benefits outweigh the risks of cycling on Britain’s roads by a factor of 20:1 (n.b. estimates from other countries place this ratio higher still). • Based on this 20:1 ratio, it can be shown that telling people to wear helmets would result in a net increase in early deaths (due to physical inactivity etc) if there was more than 1 person deterred from cycling for every 20 who continue, even if helmets were 100% effective at preventing ALL cycling injuries (i.e. not just head-only injuries). Once you factor in the proportion of serious and fatal cycling injuries that are not head-only injuries, and the at-best limited protection that helmets could provide (they are and only can be designed to withstand minor knocks and falls, not collisions with fast-moving cars or lorries), it can be shown that it only takes a fraction of a percentage point reduction in cycle use for pro-helmet policies to shorten a lot more lives than they could possibly save. In practice, the experience of enforced helmet laws is that cycle use typically falls by at least 30%, and more among teenagers. The resulting loss of cycling’s health benefits alone (let alone its environmental, economic and societal benefits) is very much greater than any possible injury prevention benefit. 

 • There is in any case a good deal of controversy about the effectiveness of helmets. They are (and can only be) designed for minor knocks and bumps, not collisions with fast cars or lorries. There is also evidence that some cyclists ride less cautiously when wearing them, that drivers leave less space when overtaking helmeted cyclists than those without, that helmeted cyclists suffer 14% more collisions per mile travelled than non-wearers, and that helmets increase the risk of neck injuries. It is therefore entirely possible that helmet-wearing might have a net disbenefit even in safety terms (a point also suggested by some of the empirical evidence), not to mention the health and other disbenefits identified above.

• There is plenty of evidence that cycling gets safer the more cyclists there are. Denmark and the Netherlands are good examples of this “safety in numbers” effect, yet very few people in those countries wear helmets. The emphasis should be on maximising the benefits of more as well as safer cycling, though measures such as 20mph speed limits, better designed roads and junctions, good cyclist and driver training, tougher and better-enforced road traffic law, and tackling the threats from lorries. By contrast, telling people to wear helmets merely drives people into increasingly car-dependent sedentary lifestyles. This would shorten far more lives than cycling does, while undermining the “safety in numbers” effect for those cyclists who remain.

Read the whole article for the evidence.. its quite interesting, if not long.