Evaluating the health benefit of bicycle helmet laws

A model is developed which permits the quantitative evaluation of the health benefit of bicycle helmet laws. The efficacy of the law is evaluated in terms of the percentage drop in bicycling, the percentage increase in the cost of an accident when not wearing a helmet, and a quantity here called the “bicycling beta.” The approach balances the health benefits of increased safety against the health costs due to decreased cycling. Using estimates suggested in the literature of the health benefits of cycling, accident rates and reductions in cycling, suggest helmets laws are counterproductive in terms of net health. The model serves to focus the bicycle helmet law debate on overall health as function of key parameters: cycle use, accident rates, helmet protection rates, exercise and environmental benefits. Empirical estimates using US data suggests the strictly health impact of a US wide helmet law would cost around $5 billion per annum. In the UK and The Netherlands the net health costs are estimated to be $0.4 and $1.9 billion, respectively.