Driving After Drug or Alcohol Use

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HIGHLIGHTS

This report contains findings about drug use and driving using data collected in the 1996 National Household Survey on Drug Abuse (NHSDA). The 1996 NHSDA included questions developed through a collaborative effort between the Substance Abuse and Mental Health Services Administration (SAMHSA) and the National Highway Traffic Safety Administration (NHTSA). The questions were designed to examine past year prevalence and patterns of driving behaviors within two hours after substance use.

The data presented in this report come from in-home personal interviews with 11,847 NHSDA respondents, age 16 and older, representing over 166 million drivers in the United States. The 166 million drivers represent only those drivers who reported driving a motor vehicle on at least one occasion in the 12 months prior to their interview and reported whether or not they drove within two hours after drug and/or alcohol use. The primary purpose of this report is to present data on driving following drug use, an area in which previous research is limited. Data on driving after alcohol use are also presented for comparison purposes. In the following summary statements, ‘driving after drug use’ refers to ‘driving within two hours after the use of drugs, with or without alcohol, in the past year’. ‘Driving after alcohol use only’ means ‘driving within two hours after the use of alcohol without the use of drugs in the past year’ unless otherwise noted. With these definitions in mind, the principal findings of this report are as follows:

•28 percent (46.5 million people) reported driving within two hours after drug or alcohol use:

-5 percent (9 million people) drove after drug use, with or without alcohol, and

-23 percent (38 million people) drove after alcohol use only.

Characteristics of Drivers Who Drove after Drug Use

•Driving after drug use was more common among drivers who were:

-Young (13% for those age 16-20 vs. 5% for those age 21 and older),

-Male (7% vs. 4% for females),

-Never married (11% vs. 3% for those who were married), and

-Unemployed (11% vs. 6% for those employed full-time).

•Driving after drug use was more common among those who reported, in the past year, being:

-Arrested (18% vs. 4% for those not arrested) or

-On probation (22% vs. 5% for those not on probation).

•Marijuana was the illicit drug used most often by drivers who drove after drug use (used by 70% of those who drove after drug use).

•Among those who reported driving after using marijuana:

-The majority reported heavy or weekly use in the past year (60%).

-Drivers age 21 and older were more likely than drivers age 16-20 to report driving after using marijuana in combination with alcohol (37% and 24%, respectively).

-More than half claimed that the marijuana use did not at all affect their ability to drive safely (56%).

-More than half perceived that they were no more likely to be stopped by police when driving after marijuana use than on other occasions (69% of those age 21 and older and 54% of those age 16-20).

•A large majority of those who drove after the use of tranquilizers and sedatives (84% and 71%, respectively) drove following the medical use of these drugs. In contrast, only 43 percent of those who drove after the use of stimulants used these drugs for medical purposes.

•Driving after drug use most commonly occurred on smaller roads (55%), in urban areas (56%), on the weekend (67%), and usually began between 6:00 p.m. and 11:59 p.m. (49%).

•The most commonly reported reasons for driving on these occasions were that drivers felt there was "no other way to get there" (69% of those age 16-20 and 59% of those age 21 and older) and that they were "not high enough to cause a crash" (57% of those age 16-20 and 60% of those age 21 and older).

Characteristics of Drivers Who Drove After Alcohol Use

•Driving after alcohol use was more common among:

-Those age 21 and older (9% of those age 16-18 and 15% of those age 19-20 vs. 29% of those age 21-34 and 17% of those age 50 and older).

-Males rather than females (31% and 14%, respectively).

•Among those who reported driving after alcohol use:

-A large majority (86%), reported low or medium past month alcohol use.

-Drivers age 16-20 were more likely than drivers age 21 and older to report heavy alcohol use (5 or more drinks on 5 or more occasions in the past month) (32% vs. 14%).

•On the most recent occasion of driving after alcohol use (with or without drugs):

-Those age 16-20 were more likely than drivers age 21 and older to report binge drinking (consuming 5 or more drinks on one occasion) (39% vs. 13%).

-Drivers age 16-20 were more likely than drivers age 21 and older to report that they drank their first and last drink in less than one hour (30% vs. 15%).

-More than one-third of drivers age 16-20 had an average estimated blood alcohol concentration (BAC) level greater than .08 g/dl (the legal limit for drivers age 21 and older in some states).

-Female drivers age 21 and older generally had higher average BAC levels than males of the same age (48% of females had a BAC level equal to or greater than 0.2 g/dl vs. 32% of males).

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This page was last updated on June 16, 2008.

SAMHSA, an agency in the Department of Health and Human Services, is the Federal Government's lead agency for improving the quality and availability of substance abuse prevention, addiction treatment, and mental health services in the United States.