At the present time, 20 states and the District of Columbia have laws requiring helmet use by all motorcycle riders, 27 states have laws requiring helmets only of riders under a certain age (usually 18) and 3 states have no laws regarding helmet use. In recent years, several states have repealed their all-rider helmet laws and so far unsuccessful efforts to repeal have occurred in others.

Motorcycle helmet laws have been a contentious issue in many states as public policy makers have debated the balance between personal freedoms and the societal costs of crashes. Those opposed to mandatory helmet laws generally argue that their individual rights are or will be infringed upon and that helmet use should be left to the choice of individual riders. Those who advocate helmet laws note that helmets are effective in reducing injury severity and that society bears a significant portion of motorcycle crash costs thereby establishing a public interest in requiring the use of reasonable safety equipment.

The 1998 universal helmet law repeal in Kentucky and the 1999 repeal in Louisiana produced similar effects. Observed helmet use dropped from nearly full compliance under the law to the 50 percent range without the law. Motorcyclist fatalities increased in the near term by sizeable amounts-by over 50 percent in Kentucky and over 100 percent in Louisiana. Injuries also increased substantially in both states. The rates of fatalities and injuries per registered motorcycle increased in both states following the helmet law repeals.

The experience in Kentucky and Louisiana is similar to the experience in Arkansas and Texas, two other states that have repealed universal laws in recent years, leaving little doubt that such repeals have demonstrable negative safety consequences. The weight of the evidence is that helmets reduce injury severity, that repeal of helmet laws decreases helmet use, and that states that repeal universal helmet laws experience increased fatalities and injuries. There is also evidence that serious head injuries increase and that treatment costs rise. Conversely, states that have adopted or reenacted universal laws have experienced declines in motorcyclist fatalities and injuries.

There are a number of factors that may influence the volume of motorcycle crashes. For instance, there has been a recent increase nationally in motorcyclist fatalities that has been attributed, in part, to an aging ridership and a trend toward more powerful motorcycles. Motorcycle registrations have also been increasing recently following many years of decline, suggesting that there may be more novice riders on the roads for the near-term. Within these global factors, helmet use plays a demonstrable role in reducing injury severity, and mandatory helmet use laws play a significant role in determining the extent of helmet use.