As the recent crash on New York’s Taconic Parkway demonstrates, it’s not just drunk driving we have to worry about on the road. Drugged driving – defined in most states as driving when a drug “renders the driver incapable of driving safely” or “causes the driver to be impaired” – is increasingly becoming a problem. In fact, drugs are used by 10 to 22 percent of drivers involved in crashes and often in combination with alcohol [NIDA, 2008].

The Long Island mother was drunk and high on marijuana the day she drove the wrong way on the Taconic, losing her own life, and killing her 2-year-old daughter, three young nieces and three men in the other car. The autopsy revealed that she had smoked marijuana no more than an hour before the wreck, and her blood-alcohol level was 0.19, more than twice the state's legal limit.

Shocking and heartbreaking, this tragic car wreck draws attention to the effects of alcohol and marijuana on drivers and the increase of drugged driving cases in the United States.

The National Highway Traffic Safety Administration (NHTSA) released findings this month in the first nationally representative estimate of illegal, prescription, and over-the-counter drug use among drivers (NHSTA, 2009). A large undertaking in itself, findings revealed that approximately 16 percent of nighttime weekend drivers tested positive for drugs — about half of them for marijuana.

Researchers acknowledged that drugs can remain in a driver's system for weeks, making it difficult to know whether those drivers were impaired while behind the wheel.

NHTSA found that 2.2 percent of drivers had blood alcohol levels of 0.08 or higher in 2007. This represents a sharp decline when comparing numbers from 1973 where 7.5 percent of the drivers surveyed were legally intoxicated.

New regulations by law enforcement agencies regarding stricter policies against drinking and driving, advocacy efforts by Mothers Against Drunk Driving and the Partnership’s community programs to reduce use of illicit and prescription drugs and alcohol have all been part of bringing about this needed change.

While the researchers acknowledged that drugs can remain in a driver's system for weeks, making it difficult to know whether those drivers were impaired while behind the wheel it has been clearly demonstrated that marijuana slows a driver’s perception of time, space, and distance (DEA).

According to the National Institute on Drug Abuse, in 2006 an estimated 10.2 million people age 12 and older reported driving under the influence of illicit drugs during the year prior to being surveyed. In 2006, 13 percent of high school seniors admitted to driving under the influence of marijuana in the previous two weeks and ten percent reported driving after having five or more drinks.