Motorcycle riding, which is both a leisure activity and a form of transportation, is enjoying renewed popularity. Motorcycles first peaked in popularity in 1973, when over 1.5 million were sold; during the 1970s, annual sales of all types of motorcycles averaged over 1 million. After 1980, sales declined, reaching a low point of less than 300,000 annually in the early 1990s. Sales began rising after 1992; sales of on-highway motorcycles rose from 186,000 in 1992 to 662,000 in 2003. The number of motorcycles in use, as measured by motorcycle registration data, has increased by at least 63% since 1997 (from 3.8 million in 1997 to 6.2 million in 2005). According to the motorcycle industry, factors influencing the increase in motorcycle ownership include affluent baby boomers returning to motorcycling after many years of not riding, and rising fuel costs. This report presents and analyzes crash data, which show that motorcycle fatalities are an increasing share of all motor vehicle fatalities in the United States. It examines the risk characteristics of motorcycles and motorcyclists, and the characteristics of fatal motorcycle crashes. The report then examines what the federal government is doing to try to reduce the rate of motorcycle fatalities. Finally, this report analyzes the issues surrounding what many experts consider to be the single most effective motorcycle safety strategy, the requirement that all motorcyclists wear a helmet that complies with federal safety standards (universal helmet law). The number of motorcycle fatalities has more than doubled over the past decade, from 2,176 in 1996 to 4,810 in 2006. Part of this increase can be attributed to a significant growth in the number of motorcyclists. According to the motorcycle industry, annual sales of on-highway motorcycles have tripled in the past decade. The Federal Highway Administration (FHWA) reports that the number of registered motorcycles increased by over 2 million (63%) during that period. But as Table 1 shows, the rate of increase in fatal motorcycle crashes (116%) and rider fatalities (115%) is almost double the rate of increase in the number of motorcycles registered (63%). By contrast, as Table 1 also shows, the number of passenger vehicle crashes and fatalities has declined (by 2% and 3% respectively) over the past decade, even though the number of vehicles registered has increased by 5%. In 2006 motorcycles represented less than 3% of all passenger vehicles registered and less than 1% of all VMT, while motorcyclist fatalities represented 14% of all fatalities suffered by operators or passengers in passenger vehicles. Among the factors that contribute to the higher rate of fatal crashes of motorcycles compared to passenger vehicles are the characteristics of both motorcycles and the motorcycle operator population. Motorcycles are inherently riskier than passenger vehicles. They are more complex to steer and less stable in braking and maneuvering. They also tend to be less noticed by other motorists compared to other passenger vehicles. In a crash motorcycles offer little protection to their occupants compared to a passenger vehicle occupant, who is enclosed in a metal frame, is required by law to be wearing a seat belt, and whose vehicle (if manufactured after 1996) is required by law to have airbags to protect the occupants of the front seat. Virtually the only protection available to a motorcyclist in a crash is a helmet and protective clothing, neither of which is required in most states. Also, an estimated 90% of motorcycle operators are male, compared to the passenger vehicle driver population, which is 50% female. Males are involved in motor vehicle accidents at a higher rate than females. As a result of both vehicle characteristics and operator characteristics, the rate of motorcycle involvement in fatal crashes, both by the number of registered vehicles and by VMT, is several times that of passenger vehicles (see Table 2 ). There were 4,489 fatal motorcycle crashes in 2005, which resulted in the deaths of 4,553 motorcyclists. Over half (53% in 2004) of motorcyclist deaths occur on weekends, and about half occur on rural roads. Forty-five percent of the motorcyclists killed in crashes in 2004 were not wearing a helmet. Speeding was judged to be a contributing factor for 37% of the fatalities. In 25% of the crashes, the motorcyclist either did not have a drivers license or lacked a motorcycle endorsement on their license. Over a quarter (27%) of the motorcyclists killed in crashes in 2005 were legally intoxicated (i.e., had an amount of alcohol in their blood (blood alcohol content, or BAC), at or above 0.08 ). Approximately half (45%) of the fatal motorcycle crashes in 2005 were single-vehicle crashes; in most of these, the motorcyclist ran off the road. Forty-one percent of the 1,878 motorcyclists who died in single-vehicle crashes were legally intoxicated. In the 56% of crashes involving two or more vehicles, the other vehicle(s) was typically a passenger car or light truck. Of two-vehicle crashes involving a passenger vehicle, 74% of the crashes involved the motorcycle striking the passenger vehicle. In more than one-third of the two-vehicle crashes, the motorist was making a left turn across the path of a motorcyclist. In looking at the characteristics of fatal motorcycle crashes during the decade 1995 to 2004, changing trends can be ascertained. The percentage of motorcycle operators in fatal crashes who had been drinking (i.e., had any alcohol in their system) declined from 42% to 34%, and the percentage who were legally impaired (BAC of 0.08 or more) declined from 34% to 28%. Likewise, the share of fatal crashes in which speeding was a factor declined from 43% to 37%. The percentage of motorcycle operator fatalities who were properly licensed increased from 63% to 75%. However, while these rates showed improvement, the actual number of fatal crashes in which alcohol or speeding played a role, and in which the driver was not properly licensed, increased. Other factors showed little or no change. For example, the rate of helmet use observed in motorcyclists involved in fatal crashes was virtually unchanged from 1995 (56%) to 2004 (57%). Other trends observed in the 1995-2004 crash data were that motorcyclists involved in fatal crashes were becoming older and riding more powerful motorcycles. The share of fatalities in which the motorcyclist was 40 years old or older rose from 25% (1995) to almost 50% (2004), pushing the average age of motorcyclists involved in a fatal crash up 19%, from 32 (1995) to 38 (2004). The share of fatal crashes involving motorcycles with engine displacements of 1,000 cubic centimeters (cc) or more rose from 30% (1995) to 41% (2004), pushing the average engine displacement of motorcycles involved in fatal crashes up 21%, from 841 cc (1995) to 1,015 cc (2004). Congress has given DOT the mission of reducing traffic deaths. As noted above, the number of passenger vehicle traffic deaths has declined over the past decade, while the number of motorcycle deaths has been increasing. In light of this, DOT has declared that motorcycle fatalities are currently the nation's greatest highway traffic safety challenge. In the most recent surface transportation reauthorization legislation, the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA) ( P.L. 109-59 , enacted August 10, 2005), Congress included several provisions relating to motorcycle safety. These included funding for a motorcycle crash causation study, the creation of a motorcycle safety grant program, and the creation of a motorcyclist advisory committee. The precondition for effective crash prevention and crash mitigation strategies is understanding why crashes happen. NHTSA has detailed information about the characteristics of fatal crashes, but without detailed information on the population of motorcyclists who are exposed to the same risks but do not experience fatal crashes, the significance of the factors observed in fatal crashes cannot be established. Such information is acquired through in-depth crash causation studies, where crashes are examined in detail and the at-risk motorcycling population in the same area at the same time is observed and interviewed. The only large scale in-depth motorcycle crash causation study in the U.S. was conducted almost thirty years ago. Since that time there have been significant changes in the characteristics of the motorcycle rider population, the highway vehicle fleet mix, and the highway environment. Section 5511 of SAFETEA authorized $2.8 million for the federal share of a motorcycle crash causation study, to be conducted jointly by FHWA and the Oklahoma Transportation Center. NHTSA had begun a smaller-scale motorcycle crash causes and outcomes study prior to the passage of SAFETEA, and after passage of SAFETEA revised that study to serve as a pilot for the larger-scale study. The final report from NHTSA's pilot study is expected in February 2008. The final report of the larger crash causation study is expected in August 2010. Section 2010 of SAFETEA creates a motorcycle safety grant program. To be eligible for a grant, a state must satisfy any two of six criteria: provide a motorcycle rider training course; provide a motorcyclist awareness program (aimed at motorists); provide an impaired driving prevention program that includes specific measures targeting impaired motorcycle driving; achieve a reduction in annual fatalities and crashes involving motorcyclists; achieve a reduction in annual fatalities and crashes involving impaired motorcyclists; or ensure that all fees collected from motorcyclists for the purpose of funding motorcycle training and safety programs are used for those programs. States that receive a grant must maintain at least the same level of spending on motorcycle safety as before the grant (that is, the grant must represent additional spending). The program is authorized at $6 million annually ($7 million in FY2009, its final year of authorization).