December 9, 2010

State Estimates of Drunk and Drugged Driving

Driving under the influence of alcohol or illicit drugs poses a significant threat to public safety because these substances can impair perception, cognition, attention, balance, coordination, and other brain functions necessary for safe driving. Driving while impaired has been linked to reckless driving, car crashes, and fatal accidents. A review of several studies found that between 5 and 25 percent of drivers involved in motor vehicle accidents tested positive for drugs, and 18 percent of motor vehicle driver deaths involved drugs.¹ Furthermore, in 2008, 32 percent of all traffic-related deaths—nearly 12,000 deaths—were the result of alcohol-related crashes.²

Recognizing the dangers associated with driving under the influence of drugs, the 2010 National Drug Control Strategy, developed by the White House's Office of National Drug Control Policy, identified the prevention of drugged driving as a national priority.³ In addition, a major component of the Substance Abuse and Mental Health Services Administration (SAMHSA) strategic initiative to reduce underage drinking and adult problem drinking is to reduce negative consequences, such as injuries resulting from impaired driving.⁴

The National Survey on Drug Use and Health (NSDUH) asks persons aged 12 or older if they had driven a vehicle while under the influence of alcohol or under the influence of illicit drugs in the past year. NSDUH defines illicit drugs as marijuana/hashish, cocaine (including crack), inhalants, hallucinogens, heroin, or prescription-type drugs used nonmedically.⁵ This issue of The NSDUH Report uses combined 2006 to 2009 data to present estimates of driving under the influence of alcohol (also referred to as "drunk driving") and driving under the influence of illicit drugs (also referred to as "drugged driving") among persons aged 16 or older by State (including the District of Columbia).⁶

State estimates are rank ordered from highest to lowest and divided into quintiles (fifths), which are presented in color-coded maps shown in Figures 1 and 2. States with the highest estimates fall into the top quintile and are shown in red on the maps; States with the lowest estimates are in the bottom quintile and are shown in blue.⁷ Additionally, the combined 2006 to 2009 data are compared with the combined 2002 to 2005 data to examine changes over time.

Combined 2006 to 2009 data indicate that 13.2 percent of persons aged 16 or older (an estimated 30.6 million persons) drove under the influence of alcohol in the past year. The rates of drunk driving were among the highest in Wisconsin (23.7 percent) and North Dakota (22.4 percent) and among the lowest in Utah (7.4 percent) and Mississippi (8.7 percent) (Figure 1).

Figure 1. Percentages of Persons Aged 16 or Older Driving under the Influence of Alcohol in the Past Year, by State: 2006 to 2009

Of the 10 States with the highest rates of drunk driving, 5 were in the Midwest (Minnesota, Nebraska, North Dakota, South Dakota, and Wisconsin), 3 were in the Northeast (Connecticut, Massachusetts, and Rhode Island), and 2 were in the West (Montana and Wyoming). Of the 9 States with the lowest rates of drunk driving, 4 were in the South (Alabama, Kentucky, Mississippi, and West Virginia), 3 were in the West (Idaho, New Mexico, and Utah), and 2 were in the Northeast (New Jersey and New York).⁸

Rates of past year drunk driving were higher among persons aged 16 to 25 than among those aged 26 or older (19.5 vs. 11.8 percent).

When combined 2002 to 2005 data are compared with combined 2006 to 2009 data, the Nation as a whole experienced a statistically significant reduction in the rate of past year drunk driving (from 14.6 to 13.2 percent), as did 12 States: Alaska, Florida, Idaho, Illinois, Maryland, Michigan, Mississippi, Missouri, New Mexico, Pennsylvania, Texas, and Washington (Table 1). No States had a statistically significant increase in the rate of drunk driving.

Reductions in past year rates of drunk driving were found both among persons aged 16 to 25 (22.2 to 19.5 percent) and among persons aged 26 or older (12.9 to 11.8 percent).

Combined 2006 to 2009 data indicate that one fifth of drunk drivers aged 16 or older (21.9 percent) drove under the influence of alcohol and illicit drugs at the same time; the rate was higher for drunk drivers aged 16 to 25 than for those aged 26 or older (38.7 vs. 15.8 percent). Comparisons of combined 2002 to 2005 data with combined 2006 to 2009 data indicate that similar percentages of drunk drivers in both time periods drove under the influence of illicit drugs and alcohol at the same time, overall and for both age groups.

Combined 2006 to 2009 data indicate that 4.3 percent of persons aged 16 or older (an estimated 10.1 million persons) drove under the influence of illicit drugs in the past year. The rates of drugged driving were among the highest in Rhode Island (7.8 percent) and Vermont (6.6 percent) and among the lowest in Iowa (2.9 percent) and New Jersey (3.2 percent) (Figure 2).

Figure 2. Percentages of Persons Aged 16 or Older Driving under the Influence of Illicit Drugs in the Past Year, by State: 2006 to 2009

Of the 10 States with the highest rates of drugged driving, 4 were in the Northeast (Massachusetts, New Hampshire, Rhode Island, and Vermont), 3 were in the West (Colorado, Montana, and Oregon), and 3 were in the South (Arkansas, Delaware, and Oklahoma). Of the 10 States with the lowest rates of drugged driving, 4 were in the South (Alabama, Maryland, Mississippi, and Texas), 3 were in the Northeast (New Jersey, New York, and Pennsylvania), 2 were in the Midwest (Iowa and South Dakota), and 1 was in the West (Utah).

Rates of past year drugged driving were about 4 times higher among persons aged 16 to 25 than among those aged 26 or older (11.4 vs. 2.8 percent).

When combined 2002 to 2005 data are compared with combined 2006 to 2009 data, the Nation as a whole experienced a statistically significant reduction in the rate of past year drugged driving (from 4.8 to 4.3 percent), as did seven States: Alaska, California, Florida, Hawaii, Iowa, Michigan, and Pennsylvania (Table 2). No States had a statistically significant increase in the rate of drugged driving.

Reductions in past year rates of drugged driving were found both among persons aged 16 to 25 (12.9 to 11.4 percent) and among persons aged 26 or older (3.0 to 2.8 percent).

Combined 2006 to 2009 data indicate that two thirds of drugged drivers aged 16 or older (66.3 percent) drove under the influence of illicit drugs and alcohol at the same time; the rate was similar for drugged drivers aged 16 to 25 and those aged 26 or older (65.8 and 66.7 percent, respectively). Comparisons of combined 2002 to 2005 data with combined 2006 to 2009 data indicate that similar percentages of drugged drivers drove under the influence of illicit drugs and alcohol at the same time, overall and for both age groups.

The Nation as a whole has seen reductions in the rates of drunk driving and drugged driving in recent years; however, each of these behaviors remains a serious problem in the United States. Although there is wide variation in the rates of impaired driving among States, no State is immune from this problem. The prevalence of impaired driving, particularly among persons aged 16 to 25, points to the need for continued prevention efforts, such as media campaigns, responsible alcohol sales and service training, sobriety checkpoints, and substance abuse assessment and treatment for those convicted of impaired driving,⁹ to reduce the incidence of impaired driving and the harm it poses.

This page was last updated on May 18, 2010.