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August 1, 2005
NIDA Director, Dr. Nora D. Volkow

There have been many education campaigns designed to inform the public about the dangers of driving under the influence of alcohol; however, it's also important to recognize that driving under the influence of drugs can be as dangerous as driving drunk.

Research has shown that driving under the influence of certain drugs can impair one's motor skills, reaction time, and judgment. While alcohol has long been recognized as a road hazard, public health officials and others are increasingly realizing that driving under the influence of drugs is a serious public safety threat as well.

Some drugs, both legal and illegal, that act on the brain, can alter an individual's perception, attention, balance, and coordination—all critical components required for safe driving. For example THC, the active ingredient in marijuana, can negatively affect coordination, memory, and judgment. As a result, a driver high on marijuana may not be able to react appropriately to unpredictable traffic conditions.

Prescription drugs also may impair drivers. In fact, many prescription drugs come with warnings against the operation of machinery (including cars and other vehicles) for a specified period of time after taking the drug.

Young drivers are particularly at risk for a number of reasons. NIDA's Monitoring the Future survey indicated that in 2004, 12.7 percent of high school seniors reported driving under the influence of marijuana, and 13.2 percent reported driving under the influence of alcohol in the two weeks prior to completing the survey. Also, it is generally accepted that because teens are the least experienced drivers as a group, they have a higher risk of being involved in an accident compared with more experienced drivers. When lack of experience is combined with the use of marijuana or other substances that impact cognitive and motor abilities, the results can be tragic.

Unfortunately, there is no widely available roadside testing device that can quickly detect drugs in a driver's system. NIDA is currently supporting research to develop testing methods and devices, and to examine the effects of drugs, particularly in combination with alcohol, on the behavioral and cognitive skills necessary for driving.

At NIDA, we will continue our efforts to support research related to drugged driving and to inform the public about these findings. For more information about this important topic, see NIDA Drugfacts on Drugged Driving.

Nora D. Volkow, M.D.