Publication Date: 
Wednesday, July 31, 2019

The Problem: Head injury is the leading cause of injury and death in bicycling accidents. Survivors of crashes may face lifelong chronic complications associated with Traumatic Brain Injury (TBI). Bicycle helmet use reduces the risk of injury by 80%, although they are underutilized by all age groups. CDC: Injury Prevention and Control. In 2015, there were over 1,000 deaths due to bicycle crashes and 467,000 bicycle related injuries. CDC: Bicycle Safety.

The Law: Many states and localities have responded to bicycle-related morbidity and mortality by mandating helmet use by bicyclists. Some states mandate helmets for all bicyclists under a certain age; 15 is a common threshold (NC GS 20.171.7, North Carolina). States enforce bicycle helmet laws with fines (e.g., California, Cal Veh Code § 21212) or by impounding the violators’ bikes (e.g., Georgia, O.C.G.A. § 40-6-296(e)(1)). For other examples of helmet laws, see Fla. Stat. § 316.2065(3)(d) (Florida) and MD Transportation Code § 21-1207.1 (Maryland).

The Evidence: Two groups of researchers have systematically reviewed studies evaluating the impact of bicycle helmet laws. Macpherson and Spinks reviewed five studies that measure the effectiveness of bicycle helmet laws as a public health intervention aimed at reducing head injuries. Macpherson A, Spinks A. Bicycle Helmet legislation for the uptake of helmet use and prevention of head injuries. Evidence-Based Child Health: A Cochrane Review Journal. 2008;3:16-32.Of the five studies, two measured the effect of such laws on the rate of helmet use and two measured the impact of the laws on bicycle related head injuries; the fifth study measured both outcomes. Based on statistically significant increases in helmet use and decreases in bicycle-related head injuries, the authors conclude bicycle helmet laws are an effective public health intervention. Karkhaneh et al. reviewed a broader sample of twelve studies assessing the effectiveness of bicycle helmet laws in increasing helmet use. Karkhaneh M, Kalenga J-C, Hager BE, Rowe BH.  Effectiveness of bicycle helmet legislation to increase helmet use: a systematic review. Injury Prevention. 2006;12(2):76-82. Across the twelve studies, seven found increases of helmet use that were greater than 30%, four found increases between 10% and 30% and one found an increase of 5%. According to the authors, the studies collectively support the effectiveness of bicycle helmet laws. 

The Bottom Line: In the judgments of the authors of a Cochrane Collaboration systematic review and the authors of a peer-reviewed systematic review, bicycle helmet laws are an effective public health intervention aimed at reducing head-related morbidity and mortality.

Additional Information: The Insurance Institute for Highway Safety, Highway Loss Data Institute provides online access to a table of state laws requiring bicycle helmet use.

Additional Resources: Insurance Institute for Highway Safety

Impact: Effective