This and the following chapter provide context for the examination of the effects of Florida's motorcycle helmet law change. This chapter briefly describes the history of motorcycle helmet laws in the United States and reviews the literature regarding helmet use and law changes. Chapter III describes recent trends in motorcycle ridership and crashes. The material is an update of that originally presented by Preusser et al., (2000).

Legislative History

The history of motorcycle helmet laws in the United States can be summarized as follows:

•  1966-1975: Most States Enact All-Rider Helmet Use Laws in Response to Federal Highway Safety Standards;

•  1976-1980: Half the States Repeal or Amend their All-Rider Helmet Use Laws after Congress Eliminates Sanctions;

•  1981-1988: Period of Stability;

•  1989-1994: Gradual Re-enactment and Congressional Encouragement; 6 States Adopt All-Rider Laws;

•  1995-2003: Congress Again Eliminates Sanctions; 6 States Drop All-Rider Helmet Laws.

The status of motorcycle helmet laws can be found at:


Also, see Preusser et al., (2000), for a more complete description of the history of motorcycle helmet laws. Figure 1 shows the number of states with universal helmet laws in effect at the end of each year, beginning in 1966. Figure 2 shows the percentage of registered motorcycles covered by all-rider laws.

Studies of Helmet Use Law Effects

The General Accounting Office (GAO, 1991), now called the General Accountability Office, conducted a broad search for studies as of 1990 and found 46 that were: published between 1975 and 1990; used data from the United States; and contained original data or original analyses and met minimum criteria for methodological soundness.

Figure 1. Chart, Universal Helmet Use Laws.
Figure 2. Chart, Percent of Registered Motorcycles Covered by Universal Helmet Law.

GAO found 9 studies that included data on helmet use in States with and without universal laws. These studies:

“reported that helmet use under universal laws ranged from 92 to 100 percent, while without a law or under a limited law [requiring only some riders to wear helmets], helmet use generally ranged from 42 to 59 percent. These data also indicated low helmet use among young riders in states with limited helmet laws”
(GAO, 1991, p. 4).

GAO found 20 studies that compared motorcycle rider fatality rates under universal helmet laws with rates during periods before enactment or after repeal of these laws.

“These studies consistently showed that fatality rates were lower when universal helmet laws were in effect; most rates ranged from 20 to 40 percent lower. Several of these studies compared periods before a helmet law was enacted, while it was in effect, and after it was repealed. They showed that the decreases in fatality rates when laws were enacted were matched by comparable increases when the laws were repealed” (GAO, 1991, p. 4).

GAO found 13 studies with data on some aspect of the societal costs of motorcycle crashes.

“These studies indicated that nonhelmeted riders were more likely to (1) need ambulance service, (2) be admitted to a hospital as an inpatient, (3) have higher hospital charges, (4) need neurosurgery and intensive care, (5) need rehabilitation, and (6) be permanently impaired and need long-term care” (GAO, 1991, p. 4).

More Recent Studies of Helmet Use

Since the 1991 GAO report a number of studies have been conducted that examine helmet use rates before and after helmet law changes. Kraus et al., (1995) observed helmet use at 60 locations in seven California counties, twice before and four times after California's 1992 adoption of an all-rider law. They concluded that helmet use increased from about 50 percent in 1991 to more than 99 percent in 1992. Preusser et al., (2000) found that following Arkansas' all-rider law repeal in 1997, helmet use declined from 97 percent to 52 percent. Texas enacted an all-rider helmet use law in 1968, repealed it in 1977 and required helmet use only for riders under 18, then re-enacted an all-rider law in 1989. Lund et al., (1991) present data showing that helmet use increased from less than 50 percent just before the 1989 universal law to 90 percent immediately after the law became effective and to 95 percent two months later. Texas again repealed its all-rider law in 1997. Preusser et al., (2000) report that this repeal was accompanied by a decline in helmet use -- from about 97 percent use before the repeal to about 66 percent after repeal. Similar findings are reported for the all-rider law repeals in Kentucky and Louisiana (Ulmer and Preusser, 2003).

More Recent Studies of Fatalities

A number of studies relating fatalities and fatality rates to helmet use laws have also appeared since the GAO report. Kraus et al., (1994) compared California's motorcycle crash experience in 1991, before adoption of its all-rider law, with 1992, after the law was in effect. Motorcycle fatalities statewide decreased 37 percent in 1992 compared with a year earlier. The fatality rate per registered motorcycle decreased 26 percent. Maryland's all-rider helmet law was adopted in 1992. Mitchell et al., (2001) used autopsy records to study the effects of the law. They reported there was a 36 percent decline in the number of motorcyclist fatalities in the 33-month period immediately following the law compared to the 33 months just prior to the law. Helmeted motorcyclists were significantly less likely to have died from traumatic brain injury as compared to non-helmeted motorcyclists after Nebraska's all-rider helmet law became effective in January 1989. Mulleman, et al., (1991) observed a 26 percent reduction in crashes per registered motorcycle in 1990, compared to the five previous years and to 5 adjoining States without all-rider helmet laws. They also studied all motorcyclists with reported crash injuries in two urban counties during 1988 and 1989 (421 in 1988 and 250 in 1989). They found that the universal law produced declines in the numbers and rates of injuries, hospital transports, hospital admissions, severe injuries to the head, and deaths. In the five full years (1984-1988) before Washington's all-rider law was adopted, the State experienced an average of 77 motorcyclist fatalities per year. In the five full years after the law (1991-1995), the average declined to 39 fatalities per year (source: FARS).

Studies of the effects of all-rider law repeals in Arkansas, Kentucky, Louisiana, and Texas have all shown substantial increases in motorcyclist fatalities comparing the two years after the laws' repeals with the two years before repeal (Arkansas +29%; Kentucky +58%; Louisiana +109%; Texas +37%). Fatalities per registered motorcycle also increased in Kentucky, Louisiana, and Texas, but not in Arkansas (Preusser et al., 2000; Ulmer and Preusser, 2003).

More Recent Studies of Injury Patterns and Costs

•  Studies of Injury Patterns

Kraus and Peek (1995) studied injured motorcyclists treated at 18 hospitals in 10 California counties between January 1, 1991 and December 31, 1993 (2,037 patients in 1991, before California adopted an all-rider law, and 2,753 in 1992 and 1993, after the law). Helmet use among these injured motorcyclists rose from 30 percent in 1991 to 86 percent in 1992 and 88 percent in 1993. Both the severity and number of head injuries per rider decreased after the law.

Mulleman et al., (1991) studied all Nebraska motorcyclists with reported crash injuries in two urban counties in the year before and the year after adoption of an all-rider law. They found that the law produced declines in the numbers and rates of injuries, hospital transports, hospital admissions, severe injuries to the head, and deaths.

Following Texas' 1989 re-enactment of an all-rider law, Mounce et al., (1992) examined hospital data from the first nine months after the law and showed that motorcyclists injured after the law suffered less serious injuries and were less likely to have head or face injuries than motorcyclists injured before the law. Fleming and Becker (1992) found a 57 percent decrease in head-related fatalities and a 55 percent reduction in severe head-related injuries among hospital-admitted motorcyclists. Following the Texas 1997 repeal of its all-rider law, Preusser et al., (2002) linked EMS and trauma registry data for motorcycle crashes and found a marked increase in traumatic brain injury cases and in the costs of treating these cases.

Washington's all-rider helmet law became effective in June 1990. Mock et al., (1995) analyzed data on motorcycle crash victims admitted to the Seattle region's only level 1 trauma center from 1986 through 1993. They report that severe head injuries decreased from 20 percent of all admitted patients before the law to 9 percent after the law.

Kelley et al., (1991) studied 398 motorcycle crash victims in eight Illinois medical centers from April through October 1988. Illinois had no helmet law at that time. They concluded that non-helmeted patients had higher overall injuries (Injury Severity Score) and more frequent head and neck injuries than helmeted motorcyclists.

Gabella et al., (1995) examined the risk of head injury in motorcycle crashes in El Paso County, Colorado in 1989-1990. Not wearing a helmet was found to increase the likelihood of a head injury by a factor of 3 relative to the risk of head injury for helmeted motorcyclists.

Kraus et al., (1995) studied 174 fatally injured and 379 non-fatally injured crash-involved motorcyclists in Los Angeles County, California, in 1988-1989, before California's all-rider helmet law. They concluded that “those not using helmets where helmet use is voluntary are a higher risk population than helmet users. They are more likely to be involved in crashes but, because they are un-helmeted, less likely to be protected against serious head injury.” Sakar, Peek, and Kraus (1995) also studied fatally injured motorcyclists in Los Angeles County. They found that head and cervical spine injuries were more frequent in non-helmeted than in helmeted fatally injured motorcyclists.

Rowland et al., (1996) studied 86 fatally injured and 386 hospitalized motorcyclists in the State of Washington in 1989 (when Washington's helmet law covered only riders under age 18). They concluded that “motorcycle helmet use is strongly and independently associated with reduced likelihood and severity of head injury, reduced overall injury severity, and reduced probability of motorcycle-related hospitalization and death attributable to head injury.”

•  Studies of Injury Costs

As part of the 1991 ISTEA legislation, Congress required NHTSA to study the effects of safety belt and motorcycle helmet use in crashes. NHTSA conducted the analysis using its Crash Outcome Data Evaluation System (CODES) data system, in which 7 States linked data from their police crash reports, emergency medical services, hospital emergency departments, hospital discharge files, claims, and other sources. NHTSA's 1996 Report to Congress found that “motorcycle helmet effectiveness ranged from 9 percent in preventing any kind of injury to 35 percent in preventing a fatality.” “The average inpatient charge for motorcycle crash victims receiving inpatient care was $14,377 for those who used helmets, and $15,578 for those who did not” (NHTSA, 1996). The CODES data showed that helmet use for motorcycle riders involved in crashes ranged from 80 to 98 percent in 3 CODES States with all-rider helmet laws and from 30 to 49 percent in 3 CODES States without all-rider laws. Helmets were estimated to be 67 percent effective in preventing brain injuries in a crash (NHTSA, 1998).

Bigelow (2001) examined CODES data from 18,394 motorcyclists involved in crashes in the State of Wisconsin. Helmeted riders were less likely to have sustained traumatic brain injury across a variety of crash related factors including crash type, speed limit, highway type, and alcohol involvement. The average hospital charge for the brain injury cases was almost $28,806 and the average length of stay was 10.6 days.

Finison (2001) examined CODES data from 806 motorcyclists involved in crashes in Maine during 1995 and 1996. Riders not wearing helmets were found to be 3 times more likely to have head injuries requiring EMS transport, hospitalization, or resulting in death than motorcyclists who were helmeted. Hospital charges were higher for those with head injury than those with other injury. Also, among the head injury cases, those who were helmeted had shorter hospital stays (4.2 days versus 9.3 days for the not helmeted) and lower treatment charges ($14,639 versus $33,443).

Shankar et al., (1992) linked all Maryland police motorcycle crash reports, hospital emergency department data and trauma registry data for a 12-month period to examine head injury and treatment cost as related to helmet use. They found that non-helmeted motorcycle operators were twice as likely to have sustained head injury and had acute care costs 3 times that of helmeted operators injured in crashes.

Max et al., (1998) examined the effects of California's 1992 adoption of its all-rider helmet law on injury costs. They found that the rate of motorcyclist hospitalizations per registered motorcycles declined by 25 percent comparing 1993 with 1991. The rate of hospitalizations for head injuries declined by 48 percent. Total hospitalization cost for motorcycle injuries declined by 35 percent comparing 1993 with 1991. Approximately three-quarters of the decline was attributed to reduced costs for patients with head injuries.

Rutledge and Stutts (1993) used the North Carolina Trauma Registry to examine the relationship of crash injury outcomes and helmet use. They compared helmeted and unhelmeted riders who were admitted to a hospital for at least a 24-hour period and found that when overall degree of injury is equalized among cases, hospital charges; length of stay; and other measures of resource utilization did not differ, but the risk of head injury was twice as high for unhelmeted riders as it was for those who were helmeted. They note that the equal resource utilization was due to the high costs of treating very severe injuries to the extremities.

Zaloshnja et al., (2004) provide extensive data on the costs of injuries to various body parts resulting from motor vehicle crashes. Medical costs for brain/intercranial injury ranged from $42,148 for minor (MAIS1) injuries to $249,356 for critical (MAIS5) injuries. Adding other costs such as police and fire services, lost wages, property damage, etc., brought the total monetary costs for a minor brain/intercranial injury to $66,790 and to $1,431,918 for a critical injury.

The studies since the 1991 GAO report overwhelmingly confirm GAO's conclusions. All available studies indicate that universal motorcycle helmet laws raise helmet use to 90 percent or higher from pre-law levels of 50 percent or lower. Conversely, repealing all-rider laws results in substantially reduced helmet use. All-rider laws are shown to reduce motorcycle fatalities, fatality rates, and severe head injuries. The studies also confirm that helmets reduce the probability of injury, of head injury, and of fatality for crash-involved motorcyclists. States that repealed all-rider helmet laws in recent years have experienced declines in helmet use and increases in fatalities and fatality rates.