Published December 2010
“Have one [drink] for the road” was once a commonly used phrase in American culture. It has only been within the past 25 years that as a Nation, we have begun to recognize the dangers associated with drunk driving. And through a multipronged and concerted effort involving many stakeholders—including educators, media, legislators, law enforcement, and community organizations such as Mothers Against Drunk Driving—the Nation has seen a decline in the numbers of people killed or injured as a result of drunk driving. But it is now time that we recognize and address the similar dangers that can occur with drugged driving.
The principal concern regarding drugged driving is that driving under the influence of any drug that acts on the brain could impair one’s motor skills, reaction time, and judgment. Drugged driving is a public health concern because it puts not only the driver at risk but also passengers and others who share the road.
However, despite the knowledge about a drug’s potentially lethal effects on driving performance and other concerns that have been acknowledged by some public health officials, policy officials, and constituent groups, drugged driving laws have lagged behind alcohol-related driving legislation, in part because of limitations in the current technology for determining drug levels and resulting impairment. For alcohol, detection of its blood concentration (BAC) is relatively simple, and concentrations greater than 0.08 percent have been shown to impair driving performance; thus, 0.08 percent is the legal limit in this country. But for illicit drugs, there is no agreed-upon limit for which impairment has been reliably demonstrated. Furthermore, determining current drug levels can be difficult, since some drugs linger in the body for a period of days or weeks after initial ingestion.
Some States (Arizona, Delaware, Georgia, Indiana, Illinois, Iowa, Michigan, Minnesota, Nevada, North Carolina, Ohio, Pennsylvania, Rhode Island, South Dakota, Utah, Virginia, and Wisconsin) have passed “per se” laws, in which it is illegal to operate a motor vehicle if there is any detectable level of a prohibited drug, or its metabolites, in the driver’s blood. Other State laws define “drugged driving” as driving when a drug “renders the driver incapable of driving safely” or “causes the driver to be impaired.”
In addition, 44 States and the District of Columbia have implemented Drug Evaluation and Classification Programs, designed to train police officers as Drug Recognition Experts. Officers learn to detect characteristics in a person’s behavior and appearance that may be associated with drug intoxication. If the officer suspects drug intoxication, a blood or urine sample is submitted to a laboratory for confirmation.
According to the National Highway Traffic Safety Administration’s (NHTSA) 2007 National Roadside Survey, more than 16 percent of weekend, nighttime drivers tested positive for illegal, prescription, or over-the-counter medications. More than 11 percent tested positive for illicit drugs.1 Another NHTSA study found that in 2009, among fatally injured drivers, 18 percent tested positive for at least one drug (e.g., illicit, prescription, or over-the-counter), an increase from 13 percent in 2005.2 Together, these indicators are a sign that continued substance abuse education, prevention, and law enforcement efforts are critical to public health and safety.
According to the 2009 National Survey on Drug Use and Health (NSDUH), an estimated 10.5 million people aged 12 or older reported driving under the influence of illicit drugs during the year prior to being surveyed.3 This corresponds to 4.2 percent of the population aged 12 or older, similar to the rate in 2008 (4 percent) and not significantly different from the rate in 2002 (4.7 percent). In 2009, the rate was highest among young adults aged 18 to 25 (12.8 percent). In addition, NSDUH reported the following:
In recent years, more attention has been given to drugs other than alcohol that have increasingly been recognized as hazards to road traffic safety. Some of this research has been done in other countries or in specific regions within the United States, and the prevalence rates for different drugs used vary accordingly. Overall, marijuana is the most prevalent illegal drug detected in impaired drivers, fatally injured drivers, and motor vehicle crash victims. Other drugs also implicated include benzodiazepines, cocaine, opiates, and amphetamines.4
A number of studies have examined illicit drug use in drivers involved in motor vehicle crashes, reckless driving, or fatal accidents. For example—
According to the Centers for Disease Control and Prevention, vehicle accidents are the leading cause of death among young people aged 16 to 19.9 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 this lack of experience is combined with the use of marijuana or other substances that impact cognitive and motor abilities, the results can be tragic.
Results from NIDA’s Monitoring the Future survey indicate that in 2007, more than 12 percent of high school seniors admitted to driving under the influence of marijuana in the 2 weeks prior to the survey.10
The 2007 State of Maryland Adolescent Survey indicates that 11.1 percent of the State’s licensed adolescent drivers reported driving under the influence of marijuana on three or more occasions, and 10 percent reported driving while using a drug other than marijuana (not including alcohol).11
Drugs acting on the brain can alter perception, cognition, attention, balance, coordination, reaction time, and other faculties required for safe driving. The effects of specific drugs of abuse differ depending on their mechanisms of action, the amount consumed, the history of the user, and other factors.
THC affects areas of the brain that control the body’s movements, balance, coordination, memory, and judgment, as well as sensations. Because these effects are multifaceted, more research is required to understand marijuana’s impact on the ability of drivers to react to complex and unpredictable situations. However, we do know that—
Prescription drugs: Many medications (e.g., benzodiazepines and opiate analgesics) act on systems in the brain that could impair driving ability. In fact, many prescription drugs come with warnings against the operation of machinery—including motor vehicles—for a specified period of time after use. When prescription drugs are taken without medical supervision (i.e., when abused), impaired driving and other harmful reactions can also result. In short, drugged driving is a dangerous activity that puts us all at risk.