EFFECTS OF BICYCLE HELMET LAWS ON CHILDREN'S INJURIES
利用医院面板数据和三重差分模型，研究发现美国自行车头盔法虽减少了儿童自行车相关头部伤害，但也导致自行车骑行减少及非头部伤害下降，同时其他轮式运动的头部伤害增加。
In recent years, many states and localities in the USA have enacted bicycle helmet laws. We estimate the effects of these laws on injuries requiring emergency department treatment. Using hospital-level panel data and triple difference models, we find helmet laws are associated with reductions in bicycle-related head injuries among children. However, laws also are associated with decreases in non-head cycling injuries, as well as increases in head injuries from other wheeled sports. Thus, the observed reduction in bicycle-related head injuries may be due to reductions in bicycle riding induced by the laws.