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Human Factors: Motorcyclist Alcohol & Other Impairment Table of ContentsHomenhtsa

Motorcyclist Attitudes

Rider Education & Training


Crash Avoidance Skills

Motorcyclist Alcohol & Other Impairment

Personal Protective Equipment


Alcohol continues to be a prominent factor in serious motorcycle crashes. Other substances and causes of impairment, including prescription drugs, over-the-counter drugs, illegal recreational drugs, environmental factors, and drowsiness, are unknown factors in motorcycle crashes.

Alcohol and other substances have been found to be major risk factors in all types of motor vehicle crashes. These factors appear to weigh more heavily in motorcycle crashes than in crashes of other vehicle types based on the following:

• In 1998, intoxication (BAC > 0.10 percent) rates for vehicle operators involved in fatal crashes were 36 percent for motorcycles, 29 percent for light trucks, 25 percent for passenger cars, and 3.0 percent for large trucks. An additional 9.0 percent of motorcycle operator fatalities had a BAC of 0.01 to 0.09 percent (Traffic Safety Facts, 1998).

• Forty-five percent of motorcycle operators killed in single vehicle crashes, and 62 percent killed in weekend-night, single vehicle crashes, were intoxicated (Traffic Safety Facts, 1998).

• Helmet use rates for intoxicated motorcyclists are lower than for those who are sober. Impaired motorcyclists involved in crashes are more likely to be speeding than those not drinking (Traffic Safety Facts, 1998).

Alcoholic beverages are frequently available and promoted where motorcycles are ridden and at events targeted to motorcyclists. Public information programs and training programs currently include information on the dangers of alcohol and motorcycling. The effects of alcohol on judgment and vehicle operation skills have been studied and quantified (Moskowitz, 1988). The number of skills needed to operate a motorcycle is known to be higher than for other motor vehicles (MSF, 1974). It is unknown at precisely what levels motorcycle-specific judgment and skills are impaired.

The effects of prescription, over-the-counter, and illegal drugs are also unknown as they relate to motorcycle crashes. In addition, motorcyclists are subjected to more direct effects of the environment such as heat and cold, and it is unknown whether these play a role in motorcycle crashes. Other sources of impairment, such as drowsiness, allergies, etc., could also play a role, but these have not been studied.


To achieve this goal of reducing motorcycle crashes where alcohol and other drugs are factors, we need a better understanding of:

• Why alcohol continues to play a role in motorcycle crashes more frequently than in those of other vehicles.

• Alcohol use and substance abuse patterns of motorcyclists.

• The role of alcohol and substance abuse, including over-the-counter medications, in motorcycle crashes.

• How alcohol, drug, and other substances and conditions impair judgment and skill.

• The role, if any, that other sources of impairment play in motorcycling.


Reducing the role of alcohol and other impairing substances in motorcycle crashes requires additional information and programs from a variety of sources. These should include:

• Increased research on the alcohol and other drug use patterns of motorcyclists and the incidence of alcohol and drug involvement in motorcycle crashes.

• Increased partnerships with groups already involved in alcohol/substance abuse issues and encouragement of new programs and approaches.

• Studying the effects of alcohol and other substances on motorcycle operating skills.

• Increased health care community involvement in detecting and counseling regarding alcohol/substance abuse.

• Encouraging the alcoholic beverage industry to promote responsible use of alcohol and provide non-alcoholic beverages at motorcycle events.

• Working with law enforcement to enforce current laws and helping them recognize motorcyclists’ alcohol/substance abuse behavior.

We need to know if and how other potential forms of impairment figure into the motorcycle safety picture and whether they should be addressed with programs. In the interim, motorcyclists should be educated that impairment does not necessarily or exclusively derive from chemical sources.


• Study how alcohol, drugs and other substances, including over-the-counter medications, can affect a motorcyclist’s operating skills.

• Study the alcohol, drug and other substance use patterns of motorcyclists.

• Continue to discourage mixing alcohol and other drugs with motorcycling.

• Educate law enforcement about unique alcohol-related behavior of motorcyclists.

• Encourage partnerships with groups already involved in alcohol/substance abuse issues related to motor vehicle crashes, e.g., Mothers Against Drunk Driving (MADD), Students Against Destructive Decisions (SADD).

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