In recent years, several states have eliminated the legal requirement that all motorcyclists wear protective helmets when riding. Effective August 1, 1997, Arkansas changed its motorcycle helmet law to require helmet use only for riders under age 21, and effective September 1, 1997, Texas required helmet use only for riders under age 21 and for older riders who have not completed a rider education course or who do not have at least $10,000 medical insurance coverage. Kentucky also repealed its universal helmet law. Effective July 15, 1998, that state required helmet use only for riders under age 21, riders operating with a learner's permit or licensed but with less than one year of riding experience. Effective August 15, 1999, Louisiana repealed its universal helmet law, thereafter only requiring riders under the age of 18 and those without at least $10,000 of medical insurance coverage to wear helmets. Florida is the most recent state to eliminate its universal helmet law, effective July 1, 2000.

The present work evaluates the effects of the helmet law changes in Kentucky and Louisiana. It follows a recently completed examination of the law changes in Arkansas and Texas (Preusser et al., 2000). To provide the appropriate context for the results, this chapter reviews the history of motorcycle helmet use laws in the United States and summarizes the effects of enacting, amending, and repealing these laws. The material is an update of that originally reported by Preusser et al. (2000).


1966-1975: Most States Enact Universal Helmet Use Laws in Response to a Federal Requirement

Prior to 1966, no state had enacted a motorcycle helmet use law. The Highway Safety Act of 1966 (P.L. 89-564) changed this situation abruptly. The Act required the Secretary of Transportation to set uniform standards for state highway safety programs. One of these standards, issued in 1967, dealt with motorcycle safety. It included the requirement that states adopt universal helmet use laws -- laws that mandate helmet use by all motorcycle riders. States that failed to comply would lose a portion of their federal-aid highway construction funds.

States immediately began to enact and implement universal helmet laws. Twenty-two states had universal helmet use laws in effect by the end of 1967 and 14 more states added laws in 1968. By 1975, 47 states and the District of Columbia had adopted universal helmet use laws.

From the first, helmet use laws generated controversy. The Illinois law, effective in 1967, was repealed in 1969 after being declared unconstitutional by the Illinois Supreme Court.

Michigan enacted a universal helmet law in 1967, repealed it in 1968, and enacted it again in 1969. Kansas enacted a universal helmet law in 1967, amended it to cover only riders under 21 in 1970, and reinstated universal coverage in 1972. Oklahoma did likewise, enacting a universal helmet law in 1967, amending it to cover only riders under 21 in 1969, and reinstating universal coverage in 1975 (finally amending it again in 1976 to cover only riders under 18).

1976-1980: Half the States Repeal or Amend their Universal Helmet Use Laws after Congress Eliminates Sanctions

In 1975, under the authority of the Highway Safety Act of 1966, the Secretary of Transportation was prepared to penalize the three states (California, Illinois, and Utah) still lacking universal helmet laws by withholding the specified portion of their federal-aid highway construction funds. This action prompted Congress to revisit the Highway Safety Act. Congress eliminated the motorcycle helmet law requirement and withdrew the potential withholding of funds from states without such laws. As a result, many states reconsidered their laws. By 1978, 25 states had repealed their universal helmet laws or amended them to cover only riders below a specified age (typically 18). Two more states did the same in 1979 and 1980, reducing the total number of states with universal helmet laws to 19 and the District of Columbia.

1981-1988: Period of Stability

In contrast to the preceding 15 years, the 1980s saw little legislative activity on the issue.. In 1983, Wyoming became the twenty-eighth state to repeal its universal law and require use only by riders under 18. In 1982, Louisiana re-enacted the universal use law it had repealed in 1976.

1989-1994: Gradual Re-enactment and Congressional Encouragement

Oregon and Texas re-enacted universal helmet use laws in 1989. Nebraska and Washington followed suit in 1990, as did Maryland in 1992. California, a state with more than 10 percent of the nation's registered motorcycles and one of only two states that had never had a helmet use law applicable to adults, implemented a universal law in 1992, following extensive debate and publicity. From 1992 to 1996, 25 states and the District of Columbia had universal helmet use laws in effect. Another 22 states had laws applicable only to young riders (usually those under the age of 18), while three states (Colorado, Illinois, and Iowa) had no use helmet law at all.

During this time, Congress once again took an interest in motorcycle helmets. In April 1990, Senators Moynihan and Chafee requested the United States General Accounting Office (GAO) to review and evaluate the available information on helmet effectiveness in preventing deaths and serious injuries, the effect of helmet laws on helmet use and motorcycle rider fatalities, and the costs to society of injuries to unhelmeted motorcyclists. GAO conducted the requested review and reported to Congress in July 1991. The report concluded that "helmet use reduces fatality rates and reduces injury severity among survivors of motorcycle accidents" and that "universal helmet laws have been very effective in increasing helmet use, virtually doubling use compared with experience without a law or with a limited law applying only to young riders. Under universal helmet laws, most states experienced 20 to 40 percent lower fatality rates than during periods without laws or under limited laws." The report recommended that "because there is convincing evidence that helmets save lives and reduce society's burden of caring for injured riders, the Congress may wish to consider encouraging states to enact and retain universal helmet laws. The Congress could return to the use of penalties [as in the 1966 Act], use incentives (e.g., making additional funds available to states that have universal laws), or use a combination of penalties and incentives" (GAO, 1991, p. 31).

With the GAO report findings as support, Congress used both a carrot and a stick to promote universal helmet laws as part of the Intermodal Surface Transportation Efficiency Act of 1991, commonly known as ISTEA. The carrot was additional federal funding for states. ISTEA provided special "incentive" grants to states with both universal motorcycle helmet laws and passenger vehicle safety belt use laws. A state qualified for a first-year grant by having these two laws in effect. In subsequent years, the state also was required to exceed minimum motorcycle helmet and safety belt use levels (helmet use of 75 percent in the second year and 85 percent in the third year). Twenty-three states and the District of Columbia received grants for one or more of the fiscal years 1992, 1993, and 1994 for which the grants were authorized.

As the stick, ISTEA provided that states without both a universal motorcycle helmet law and a safety belt use law by October 1, 1993, would have a portion of their fiscal year 1995 Federal-aid highway funds transferred to their highway safety programs. As most states had safety belt use laws in place, the provision's main goal was to encourage states to enact universal helmet laws.

The carrot and stick had little effect on state motorcycle helmet laws. Maryland has been the only state to enact a universal helmet law since 1992. At the end of fiscal year 1995, twenty-three states had safety belt use laws but did not have universal helmet laws by October 1993 and consequently saw the specified portion of their Federal-aid highway funds transferred in that fiscal year. Three additional states had a universal helmet law but lacked a safety belt use law, and two states lacked both laws.

1995-2001: Congress Acts Again; Five States Drop Universal Helmet Laws

In November 1995, as part of the National Highway System Designation Act, Congress repealed the ISTEA transfer provision for states lacking universal helmet laws, effective with fiscal year 1996. Efforts to amend or repeal universal helmet laws grew in many states and, as noted, Arkansas, Florida, Kentucky, Louisiana and Texas repealed their laws. At the end of 2001, 20 states and the District of Columbia had universal helmet laws in effect. Another 27 states had laws applicable only to some riders (typically riders under a specified age), while three states had no helmet law at all. (1) Figure 1 shows the number of states with a universal helmet law in effect at the end of each year, beginning in 1966. The shaded states in Figure 2 are those with a universal helmet law in effect at the end of 2001.

Figure 1. Universal Helmet Law States

figure - states with universal helmet laws by year 1966 - 2000

(1)The states with universal helmet laws at the end of 2001 were AL, CA, GA, MD, MA, MI, MS, MO, NB, NV, NJ, NY, NC, OR, PA, TN, VT, VA, WA and WV. States with no helmet laws were CO, IL and IA. See the Appendix for State Helmet Law History.

Figure 2. Helmet Law Status in 2001

figure - u.s. map showing states with universal helmet laws

Highlighted states have universal helmet laws.


The effects of state helmet law enactment and repeal have been studied in great detail. GAO's 1991 review summarizes all studies available in 1990. The GAO study and studies that have appeared since the GAO review are discussed below.

1991 GAO Review of Helmet Use Law Studies

GAO conducted a broad search for studies as of 1990 and discovered 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" (GAO, 1991, p. 2).

GAO found nine 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 twenty 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 thirteen studies with data on some aspect of the societal costs of motorcycle accidents.

"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).

Studies Since 1990

Several studies have appeared since GAO's review. Some investigate the effects of enacted helmet laws in several states. Others provide new data on the effectiveness of helmets in preventing injury.

Arkansas was among the first group of states that adopted a universal helmet law in 1967. That law was repealed as of August 1, 1997. Preusser et al. (2000) found that following the law repeal, helmet use declined from 97 percent to 52 percent while fatalities and injuries increased. The percentage of cases involving head injury also increased.

Arkansas has relatively few motorcyclists fatalities per year. In the three years before the repeal (1994-1996) the state experienced an average of 21 motorcyclists killed per year. This increased to 25 killed per year in the three years after the law change (1998-2000).

California's universal helmet law became effective in January 1992. Kraus et al. (1995) observed helmet use at 60 locations in seven California counties, twice before and four times after California's law became effective. They concluded that helmet use increased from about 50 percent in 1991 to more than 99 percent in 1992.

Kraus et al. (1994) compared California's motorcycle crash experience in 1991, before the law, with 1992, after the universal law. Motorcycle fatalities statewide decreased 37 percent in 1992 compared with a year earlier. The fatality rate per registered motorcycle decreased 26 percent.

There is now considerably more data regarding motorcycle fatalities in California since its adoption of a universal helmet law. In the five years immediately before the universal law (1987-1991), the annual average of motorcyclists killed was 596. In the five years following adoption (1992-1996), the average was 274, a 54 percent decrease. Figure 3 shows the trend in the state's motorcyclist fatalities over the 1987-2000 period. Prior to the adoption of the universal helmet law, fatalities had declined from 716 in 1987 to 505 in 1991. A sharp decline was then experienced following enactment of the law. This was followed by gradual declines through 1998, then increases in 1999 and 2000, mirroring national trends.

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 the 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.

Figure 3. California Motorcyclists Killed, 1987-2000 (Source: FARS)

figure - number killed versus year 1987 - 2000

Maryland's universal helmet law was adopted in 1992. Mitchell et al. (2001) used autopsy records to study the effects of the law. They reported that 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. In the five years prior to the law's adoption (1987-1991) the state averaged 49 motorcyclist fatalities per year. In the five years after the law's passage (1993-1997) the state averaged 28 motorcyclist fatalities. However, as shown in Figure 4, fatalities have been on the increase in recent years.

Figure 4. Maryland Motorcyclists Killed, 1987-2000 (Source: FARS)

figure - number killed versus year 1987 - 2000

Nebraska's universal helmet law became effective in January 1989; a previous universal law had been declared unconstitutional by the Nebraska Supreme Court and was repealed in 1977. Mulleman, Mlinek, and Collicott (1991) observed a 26 percent reduction in crashes per registered motorcycle in 1990, compared to the five previous years and to five adjoining states without universal 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 sharp declines in the numbers and rates of injuries, hospital transports, hospital admissions, severe injuries to the head, and deaths.

Nebraska is another state with relatively few motorcyclist fatalities. Nevertheless, in the five years just prior to adopting a universal helmet law, the state averaged 24 fatalities per year. In the five years just after the universal law, fatalities declined to an average of 10 per year. In 2000 the state experienced just three motorcyclist fatalities.

Texas enacted a universal helmet use law in 1968, repealed it in 1977 and required helmet use only for riders under 18, and re-enacted a universal helmet law in 1989. Lund, Williams, and Womack (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.

Mounce et al. (1992) found an 11 percent reduction in serious injury crashes per registered motorcycle after the law, using police-reported data. Hospital data from the first nine months after the law 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 13 percent reduction in fatalities and in severe injuries in the first 12 months after the universal law was reinstated, after using time series methods to control for long-term declines in motorcycle fatalities. They found a 57 percent decrease in head-related fatalities and a 55 percent reduction in severe head-related injuries among hospital-admitted motorcyclists.

Effective September 1, 1997 Texas again repealed its universal helmet law and thereafter required helmet use only by riders under age 21 or who had not completed a rider education course or who did not have at least $10,000 medical insurance coverage. Preusser et al. (2000) found that the 1997 repeal was accompanied by a decline in helmet use, an increase in fatalities, while non-fatal injuries did not change appreciably. However, there was a marked increase in traumatic brain injury cases and in the costs of treating these cases. Also, in the three years immediately following the law change (1998-2000), an average of 180 motorcyclists were killed each year compared to an average of 119 in the three years (1994-1996) before the law change; a 51 percent increase. See Figure 5.

Figure 5. Texas Motorcyclists Killed, 1994-2000 (Source: FARS)

figure  - number of fatalities versus year 1994 - 2000

Washington's universal helmet law became effective in June 1990. Mock et al. (1995) analyzed 992 motorcycle crash victims admitted to the Seattle region's only level 1 trauma center from 1986 through 1993. They found that severe head injuries decreased from 20 percent of all admitted patients before the law to 9 percent after the law. Mortality among admitted patients decreased following the law.

In the five full years (1984-1988) before the universal law was adopted, Washington averaged 77 motorcyclist fatalities per year. In the five full years after the law (1991-1995), the average declined to 39 fatalities per year.

Helmet Effects. 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 seven 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).

Additional analyses of the CODES data showed that helmet use for motorcycle riders involved in crashes ranged from 80 to 98 percent in three CODES states with universal helmet laws and from 30 to 49 percent in three CODES states without universal laws. Helmets were found to be 65 percent effective in preventing brain injuries in a crash (NHTSA, 1998a).

Sosin, Sacks, and Wilson (1990) used National Center for Health Statistics Multiple Cause of Death data to study motorcycle fatalities from 1979 through 1986. They found that 53 percent of the 28,749 motorcycle fatalities were associated with head injuries. Rates per population for motorcycle fatalities associated with head injury (adjusted by age, sex, and race) were almost twice as high in states without universal helmet laws as in states with universal helmet laws. Fatalities per registered motorcycle also were greater in states without universal helmet laws. In the two states that dropped universal coverage during the study period, motorcyclist fatalities per population rose substantially: by 184 percent in South Carolina and by 73 percent in Wyoming.

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 unhelmeted patients had higher overall injuries (measured by the Injury Severity Score) and more frequent head and neck injuries than helmeted motorcyclists.

Kraus et al. (1995) studied 174 fatally injured and 379 nonfatally injured crash-involved motorcyclists in Los Angeles County, California, in 1988-1989, before California's universal 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 unhelmeted, less likely to be protected against serious head injury."

Sakar, Peek, and Kraus (1995) studied 173 fatally injured motorcyclists in Los Angeles County, California between July 1, 1988, and October 31, 1989. They concluded that head and cervical spine injuries were more frequent in unhelmeted 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."

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 charges 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 the State of Maine during 1995 and 1996. Riders not wearing helmets were found to be three times more likely to have head injuries requiring EMS transport, hospitalization, or resulting in death than motorcyclists who were helmeted.


The studies since the 1991 GAO report confirm GAO's conclusions with more recent data. All studies concluded that universal motorcycle helmet laws raise helmet use to 90 percent or higher from pre-law levels of 50 percent or lower. Universal laws 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.