According to a forthcoming study in the Journal of Law and Economics, bicycle helmet compulsion for children brings with it a likely drop in the amount of youth cycling. Children don't exercise any less, finds the study, but children ditch cycling and switch to other sports and activities.
The study - Intended and Unintended Consequences of Youth Bicycle Helmet Laws [PDF] - is by economists Christopher S. Carpenter of the Merage School of Business at the University of California, and Mark F. Stehr of the LeBow College of Business at Drexel University.
The professors show that, in America, 650,000 fewer children ride bikes each year after helmet laws go into effect.
"As other states consider helmet laws as a way to reduce bicycling related injuries and fatalities, they should keep in mind that although the laws increase helmet use and reduce fatalities, they are also likely to reduce bicycling among the targeted group," says the study.
The professors conclude that "in addition to the increase in helmet use, there is also robust evidence for an unintended and previously undocumented mechanism: helmet laws produced modest but statistically significant reductions in youth bicycling participation of 4-5 percent…[but that] it is likely that overall bicycling miles travelled fell even more."
An emotive argument used often for cycle helmet compulsion is: "If legislation can save just one life, it will be worth it."
Helmet law opponents say that such an argument could be equally applied to compulsory helmets for child soccer players, pedestrians, and children ferried around in cars, all activities that have seen child fatalities caused through head injuries.