Drugs and alcohol impair many functions of the brain, making it very difficult to perform everyday tasks like driving a car. The substances can cause problems with perception and coordination, as well as balance and other brain functions necessary for the safe operation of a vehicle.

A recent report by the Substance Abuse and Mental Health Services Administration detailed the extent of drunk and drugged driving by each state. As background information, SAMHSA indicated that in a review of several studies, it was determined that between 5 and 25 percent of drivers involved in accidents tested positive for drugs.

In addition, approximately 18 percent of fatal accidents involved drugs. A 2008 report showed that 32 percent of fatal accidents were influenced by the use of alcohol by the driver.

In an effort to reduce the rates of drugged and drunk driving through strategic educational programs, the National Survey on Drug Use and Health surveys individuals aged 12 and older about their driving choices while under the influence of alcohol or illicit drugs. The recent report from NSDUH includes information gathered from 2006 to 2009 from persons aged 16 years or older.

Of the states that showed the highest rates of drunk driving, five were in the Midwest (Minnesota, Nebraska, North Dakota, South Dakota and Wisconsin), three were in the Northeast (Connecticut, Massachusetts, and Rhode Island), and two were in the West (Montana and Wyoming). Rates of drunk driving were higher among those aged 16 to 25 than those over the age of 26.

The report indicated that there is also a significant problem with individuals driving under the influence of a combination of drugs and alcohol. Combined data from 2006 to 2009 shows that approximately one fifth of drunk drivers were also under the influence of illicit drugs at the same time. Once again, the rate was higher for younger drivers, with those aged 16 to 25 more likely than older drivers to use drugs and alcohol together while driving (38.7 versus 15.8 percent).

The highest rates of driving under the influence of drugs alone were found in Rhode Island (7.8 percent) and Vermont (6.6 percent). The lowest rates were found in Iowa (2.9 percent) and New Jersey (3.2 percent). Rates of drugged driving were 4 times higher among persons aged 16 to 25 than they were among older drivers.

The United States has seen an overall reduction in rates of drunk and drugged driving. However, the information provided in the report is important for further reducing the number of lives affected by this dangerous behavior. The report especially highlights the need for targeted education and intervention among younger drivers who make up the bulk of the drunk and drugged drivers.