Motorcycle Helmets

WHEREAS brain injury is a leading cause of death in motorcycle crashes, and

WHEREAS motorcycle helmets that meet national standards significantly reduce the likelihood of a serious brain injury in the event of a crash, and

WHEREAS motorcycle helmets are effective in preventing crash-related fatalities and brain and facial injuries among motorcycle riders, and

WHEREAS universal motorcycle helmet use laws have been shown to significantly increase helmet use and are easily enforced because of the high visibility of motorcycle riders, and

WHEREAS motorcycle helmet laws applying only to minors or underinsured riders are more difficult to enforce and are less effective in promoting helmet use by motorcycle riders, and

WHEREAS motorcycle crash-related injuries and fatalities have been shown to decrease following enactment of a universal helmet law, and

WHEREAS motorcycle crash-related injuries and fatalities have been shown to increase following the repeal or weakening of motorcycle helmet laws, and

WHEREAS hospital costs of motorcycle crash-related injuries are higher among unhelmeted operators than helmeted operators, and

WHEREAS motorcycle injury costs are shared by all citizens via health care costs and health care insurance, and not just by the injured motorcyclists,

BE IT RESOLVED that the Association for the Advancement of Automotive Medicine urges all countries, provinces, and/or states to adopt and enforce legislation mandating that all persons riding on a motorcycle wear a properly-fitted and secured helmet that meets national motorcycle helmet standards.

Adopted: 2011, updated 2018 

AAAM White Paper in support of Motorcycle Helmet Policy 2018

Laws requiring motorcyclists to wear helmets are in effect in most countries outside the United States. The first motorcycle helmet use law in the world took effect on January 1, 1961, in Victoria, Australia. A seminal study conducted in the 1970s known as the “Hurt Report” investigated over 900 motorcycle crashes and concluded that the only significant protective equipment for motorcyclists is a qualified safety helmet and that there was no reason for a motorcycle rider to be without a helmet.1 A European project entitled Motorcycle Accident In-Depth Study (MAIDS) also thoroughly investigated over 900 motorcycle and moped crashes in 1999 and 2000 and found the helmet to be the most significant form of personal protective equipment.2 All five countries involved in MAIDS had mandated helmet use for all riders. However, in the United States, fewer than half of the states currently have laws requiring all motorcyclists to wear a helmet (i.e., “universal helmet laws”). A pattern of enactment, repeal, reinstatement, or weakening of universal helmet laws has provided a natural laboratory to evaluate the effects of wearing helmets and the effects of universal helmet laws.

According to the US National Highway Traffic Safety Administration (NHTSA), from 2006 to 2015 approximately 5,000 people have been killed and 90,000 have been injured on motorcycles annually.3 The number of deaths per 100 million vehicle miles traveled on motorcycles in 2015 was 25.38, about 29 times that of passenger cars, and the number of motorcyclist injuries was 451 per 100 million vehicle miles traveled, approximately 5 times that of passenger car occupants.

Scientific research has consistently demonstrated the protective effect of motorcycle helmets, both in the laboratory and in the field. Motorcycle helmets were estimated to have saved 1,772 lives in 2015, and it was further estimated that another 740 lives would have been saved if helmets were worn 100% of the time.3 To receive approval from the United States Department of Transportation (DOT), motorcycle helmets must conform to NHTSA’s Federal Motor Vehicle Safety Standard (FMVSS) 218.4 This standard sets forth rigorous criteria for laboratory testing and evaluation of penetration, impact attenuation, and retention of motorcycle helmets. Helmets that do not conform to this standard are often referred to as “novelty helmets.”

In a comparative study, novelty helmets had head-injury criterion values (a measure of the likelihood of head injury after an impact) of more than three times that of DOT-approved, full-face helmets in the FMVSS 218 headform drop test protocol.5 This test result correlated to a 91% chance of a significant brain injury, scored as at least a “4” on the Abbreviated Injury Scale (AIS) versus a 4% chance of an AIS 4+ brain injury with a DOT-approved, full-face helmet. Novelty helmets have also fared poorly in field research; a review of motorcycle crashes in California in 2012-2013 cited an adjusted fatal injury risk ratio of 1.95 for novelty to DOT-approved, full-face helmets.6 Because of this difference, most field research studies comparing helmeted and unhelmeted motorcyclists consider those who wore a novelty helmet to be unhelmeted.

In the field, DOT-approved helmets have been shown to significantly reduce the severity of injury in non-fatal crashes. The effectiveness of helmets in preventing fatalities varies among studies, but most studies indicate some level of protective effect. One study of motorcycle crashes analyzed data from 1980-1998 in the Fatality Analysis Reporting System (FARS) database involving a driver and passenger in which at least one of the riders was killed.7 This study found the relative risk of death for a helmeted rider was 0.61, or a 39% risk reduction. A study of crashes in the American College of Surgeons National Trauma Data Bank from 2007-2014 showed unhelmeted motorcyclists admitted to hospitals after crashes had significantly higher proportions of Glasgow Coma Scale (GCS) scores of less than 9 (14% vs. 8%), head injuries with AIS scores greater than 2 (28% vs. 15%), injury severity scores (ISS) greater than 15 (33% vs. 30%), traumatic brain injuries (TBI) (21% vs. 11%), and mortality (4% vs. 2%) compared to helmeted motorcyclists.8 A similar study of over 5,000 crashes from 1994-2002 showed that unhelmeted riders were approximately twice as likely to have a facial injury (39% vs. 20%) and more than twice as likely to suffer a brain injury of AIS greater than three (33% vs. 14%).9 This study also showed much higher rates of death at the scene (8% vs. 4%) and death after hospital admission (7% to 4%) for unhelmeted riders. An analysis of 2011-2015 crashes from the FARS database showed a higher injury-to-fatality ratio for helmeted (19.87) versus unhelmeted (15.13) riders, meaning that helmeted riders were about 30% more likely to be injured rather than killed when wearing a motorcycle helmet. A chronological evaluation of motorcycle helmet effectiveness in preventing death found that helmets increased in efficacy from 29% in 1982-1987 to 37% in 1993-2002.10 Researchers attributed the increased effectiveness of motorcycle helmets to technological improvements in motorcycle helmet design and materials, and it is reasonable to theorize that this trend will continue as the state of the art in motorcycle helmet technology improves.

One caveat to wearing a motorcycle helmet is that it must properly fit and be well-secured to the user’s head. The Hurt Report of the 1970s noted that a loose-fitting helmet may cause the helmet to rotate and slip off even with the retention system fastened.1 With the retention system not secured, even minor impacts can easily dislodge the helmet from the head, leaving the rider’s head unprotected. Hurt found that 6% of motorcycle riders in the crashes investigated did not have the retention system fastened. That research also found that a correctly-fitting, securely-fastened full-face helmet would be retained during a crash. The crashes evaluated in the MAIDS found 9% of riders’ helmets were not retained, with approximately 70% of those due to improper fastening or modification of the retention system.2 A 2011 study in Taiwan found that motorcyclists with loosely fastened helmets increased their risk of head injury 1.94 times and their risk of brain injury 2.50 times compared to motorcyclists with firmly fastened helmets.11

Stark changes in usage and outcomes have been correlated to enactment, repeal, and weakening of universal helmet laws in numerous states. Helmet usage rates in states with a universal helmet law generally range between 90% and 100%, whereas states with only a partial helmet law based on age and/or level of insurance have rates of just 40% to 50%, and states with no law have rates below 20%.12,13 This is likely true internationally, as well, with the European MAIDS reporting usage rates over 90% in universal helmet law regions.2 In a study of motorcycle crashes from 2005-2008 specifically comparing universal helmet law states to partial helmet law states, the relative risk in partial helmet law states for facial injury (1.60), head injury (1.35), and a traumatic brain injury (1.09) was significantly greater than in universal helmet law states, while the fatality rate at the scene (3%) and in the hospital (3%) was about the same.12

Several investigations have specifically looked at states that have made changes to their helmet laws in recent years. In the late 1990s and early 2000s, Arkansas, Texas, Kentucky, Louisiana, and Florida all repealed and/or modified their universal helmet laws. Helmet usage rates in these states dropped precipitously within the first few years of the law change from nearly 100% to around 50%-60%.10,13-16 While national trends for motorcycle registrations and miles traveled by motorcycles in the late 1990s and early 2000s increased substantially, the number of motorcycle crashes resulting in injury and death increased at even higher rates in states that had repealed their universal helmet law. In Florida, there was an 81% increase in fatalities during the three years after the law change compared to the three years prior to the change.10 Kentucky and Louisiana respectively saw 37.5% and 75% increases in fatalities when comparing the two years before to the two years after the law repeal,14 while Arkansas and Texas respectively saw 21% and 31% increases in motorcycle operator fatalities.16 As injuries in motorcycle crashes decreased 3% nationally from 1997-2001, increases in injuries of motorcycle operators of 17% and 21% were seen in Kentucky and Louisiana, respectively.14

Michigan repealed its universal helmet law in 2012. Helmet usage decreased from 94% during elmet usage decreased from 94%       the 12 months before the repeal of the law to 71% during the 12 months following repeal. In addition, there was a shift in the type of injury with fewer concussions (56% to 46%) but more skull fractures (23% to 32%), though fatality rates stayed about the same (3%).17 Odds ratios for fatalities (1.84) and head injuries (2.31) for unhelmeted motorcyclists were much higher than their helmeted counterparts.

Conversely, California implemented a universal helmet law in 1992, and helmet usage by motorcycle operators rose rapidly from 46% four months before the law to 99% one month after the law.18 Motorcycle crash-related fatalities in California in the year following enactment of the universal helmet law decreased 37%, and head injuries among nonfatally injured motorcyclists also significantly decreased.19 A similar result was seen in Nebraska when it enacted its universal helmet law in 1989. There was a 26% decrease in reported motorcycle crashes, and serious head injuries (AIS 3+) decreased 22%.20 Likewise, the 1992 enactment of a universal helmet law in Maryland was followed by a 37% decrease in motorcycle crash-related fatalities.21

The economic impact of universal helmet laws is also compelling. An analysis of crashes from 2005-2008 found that, when compared to states with universal helmet laws, median charges for an emergency department visit were $543 more in partial helmet law states, and median charges for those hospitalized were over $6,000 more in partial helmet law states.12 A 2014 meta-analysis of literature on the costs associated with not wearing a helmet found that unhelmeted motorcyclists averaged over $12,000 more in hospital costs and also had increased post-discharge care costs.22 NHTSA’s National Center for Statistics and Analysis estimated motorcycle helmets saved $3 billion in economic costs and $19 billion in comprehensive costs in 2015.23 Economic costs include lost productivity, medical costs, legal and court costs, emergency service costs, insurance administration costs, congestion costs, property damage, and workplace losses. Comprehensive costs include economic costs plus the valuation for lost quality of life. As medical costs continue to rise, it is reasonable to expect that the disparity in costs between helmeted and unhelmeted riders will also increase.

Universal helmet laws appear to have a complex effect in achieving reduced fatality and injury rates. In addition to protecting against energy transfer to the brain during a crash, there is evidence to suggest that universal helmet laws may reduce motorcycle riding, especially for passengers.18 It has been theorized that the high-risk group of motorcyclists who are unwilling to purchase and/or wear a helmet may drop out of the riding population or at least restrict their mileage because of law enactment. While other factors such as motorcycle characteristics, impaired riding, speeding, demographic changes in ridership, education, and training may also affect some of the statistics related to universal helmet laws, the protective effect of motorcycle helmets is unquestioned, and injury and fatality rates are consistently reduced significantly when wearing a DOT-approved helmet while riding.

Weak helmet laws based on age or insurance coverage are difficult to enforce and have been comparatively ineffective.15 After Florida repealed its universal helmet law, deaths of riders under 21 years of age, who were still required to wear a helmet, increased 188%.24 Unfortunately, universal helmet laws have also been correlated with higher use of novelty helmets. In Florida, repeal of the universal helmet law led to a reduction in novelty helmet use from 40% to 6%,15 indicating that many riders were using inadequate head protection while riding to comply with the law. Therefore, an emphasis on only using motorcycle helmets that meet industry standards, such as FMVSS 218, is critical.


1Hurt, H.H., Ouellet, J.V., and Thom, D.R. 1981. Motorcycle Accident Cause Factors and Identification of Countermeasures. Report no. DOT HS-5-01160. Washington, DC: US Department of Transportation.

2Association of European Motorcycle Manufacturers. 2009. Motorcycle Accident In-Depth Study. Brussels: Association of European Motorcycle Manufacturers.

3National Highway Traffic Safety Administration. 2017. Traffic safety facts, 2015. Report no. DOT HS-812-353. Washington, DC: US Department of Transportation.

4Code of Federal Regulations Title 49 (2006), Chapter V-National Highway Traffic Safety Administration, Department of Transportation, Part 571-Federal Motor Vehicle Safety Standards, Standard No. 218-Motorcycle helmets, 10-1-2006 Edition.

5Scher, I.S., Harley, E.M., Richards, D., and Thomas, R. 2009. Likelihood of Brain Injury in Motorcycle Accidents: A Comparison of Novelty and DOT-Approved Helmets. SAE Paper No. 2009-01-0248. Society of Automotive Engineers, Warrendale, PA.

6Rice, T.M., Troszak, L., Erhardt, T., Trent, R.B., and Zhu, M. 2017. Novelty helmet use and motorcycle rider fatality. Accident Analysis and Prevention, 103:123-128.

72002 – Association of Helmet Use with Death in Motorcycle Crashes: A Matched-Pair Cohort Study

82017 – The impact of helmet use on outcomes after a motorcycle crash

92006 – Economic Impact of Motorcycle Helmets – From Impact to Discharge

102005 – Evaluation of the Repeal of the All-Rider Motorcycle Helmet Law in Florida

112011 – Effectiveness of different types of motorcycle helmets and effects of their improper use on head injuries

122015 – Crash Outcome Data Evaluation System (CODES): An Examination of Methodologies and Multi-State Traffic Safety Applications

132008 – The effects of a mandatory motorcycle helmet law on helmet use and injury patterns among motorcyclist fatalities

142003 – Evaluation of Repeal of Motorcycle Helmet Laws in Kentucky and Louisiana

152004 – Florida Motorcycle Helmet Use Observational Survey and Trend Analysis

162000 – Evaluation of Motorcycle Helmet Law Repeal in Arkansas and Texas

172017 – The Impact of Michigan’s Partial Repeal of the Universal Motorcycle Helmet Law on Helmet Use, Fatalities, and Head Injuries

181995 – Compliance with the 1992 California Motorcycle Helmet Use Law

191994 – The Effect of the 1992 California Motorcycle Helmet Use Law on Motorcycle Crash Fatalities and Injuries

201992 – Motorcycle crash injuries and costs: Effect of a reenacted comprehensive helmet use law

212002 – Autopsy Study of Motorcyclist Fatalities: The Effect of the 1992 Maryland Motorcycle Helmet Use Law

222014 – The Economic Impact of Helmet Use on Motorcycle Accidents: A Systematic Review and Meta-analysis of the Literature from the Past 20 Years

232017 – Lives and Costs Saved by Motorcycle Helmets

242005 – Traffic Safety Facts Traffic Tech – Florida’s Motorcycle Helmet Law Repeal