Mandatory Helmet Use and the Severity of Motorcycle Accidents: No Brainer?

We study the impact of mandatory motorcycle helmet use laws on the severity and volume of road accidents in Uruguay by exploiting a change in the enforcement of the traffic law. Using a difference-in-differences design based on an unexpected change in policy, we report a sharp increase in helmet use and a five percentage point reduction in the incidence of serious or fatal motorcyclist accidents from a baseline of 11 percent. The benefits of helmet use are disproportionately borne by groups more likely to experience serious injuries, such as males or young drivers. We find no evidence of other responses in terms of either the volume or type of accident, suggesting that motorcyclists’ behavior did not respond to differences in risk. We show that additional costs of enforcement for the relevant government agencies were negligible and estimate the health benefits of the policy.

本研究依托乌拉圭交通法规执法力度的一项变动，探讨强制佩戴摩托车头盔法令对该国道路交通事故严重程度与事故总量的影响。本研究采用基于突发政策变动的双重差分法（difference-in-differences）设计，研究发现头盔佩戴率大幅提升，且摩托车手严重或致命事故的发生率较11%的基准水平下降了5个百分点。头盔佩戴的健康收益更多惠及更易遭受严重伤害的群体，例如男性骑手与青年驾驶者。本研究未发现事故总量或事故类型存在其他变化的证据，表明摩托车骑手的行为并未因风险差异而发生改变。此外，本研究证实相关执法部门为此新增的执法成本可忽略不计，并估算了该政策带来的健康收益。