Do Bike Helmets Really Reduce Injuries?

Are bike helmets dangerous?

A report last week from the National Bureau of Economic Research (NBER), along with other evidence, shows that this may be the case. The report by Pinka Chatterji and Sara Markowitz, titled "Effects of Bicycle Helmet Laws On Children's Injuries," examines the effect of recent bicycle helmet laws on children who ride bikes. Although the researchers found that the laws correlated to reduced head injuries, the report also indicated that such a reduction may have been caused by reduced bicycle riding as a result of the laws.

James Hamblin further discusses the issue in an article in "The Atlantic" published Friday March 8, 2013. Hamblin cites research conducted in 2006 showing that drivers tended to pass closer to cyclists wearing helmets than to those who did not. As Chatterji and Markowitz point out in their study, we live in a culture that often shames people into either wearing a helmet or not riding at all. Guilt over not wearing a helmet or safety concerns over not having one handy may prompt us to drive instead, which begs the question of which is a better option.

The report from the NBER indicates that teenagers and children ride their bikes less in locations with helmet laws in place. The report points out that less riding could be what actually accounts for the reduction in injuries. It also notes that those on roller skates and skateboards are more aggressive when wearing helmets, resulting in more injuries. It says this could be the same case with bicycle riders.

"Yes, there are studies that show that if you fall off a bicycle at a certain speed and hit your head, a helmet can reduce your risk of serious head injury," wrote Elisabeth Rosenthal in The New York Times last fall. "But such falls off bikes are rare — exceedingly so in mature urban cycling systems. On the other hand, many researchers say, if you force or pressure people to wear helmets, you discourage them from riding bicycles .... The safest biking cities are places like Amsterdam and Copenhagen, where middle-aged commuters are mainstay riders and the fraction of adults in helmets is miniscule."

What do you think of the NBER's report? Are bike helmets dangerous?