Drivers often underestimate the risks of getting behind the wheel while under the influence of drugs, according to a recent report by the Governors Highway Safety Administration, and drugged driving is becoming a more prevalent issue in the United States. The organization says that while problem is more difficult to address than alcohol-impaired driving, several steps can help with education on the topic as well as enforcement.

The GHSA suggests that states should be better prepared for drugged driving due to more lenient laws on the use of marijuana as well as the increased use of prescription drugs. Twenty-three states, including Connecticut, allow marijuana use for medical purposes while four states and the District of Columbia permit its recreational use as well. Prescription drug use has quadrupled since 1999, according to the Centers for Disease Control and Prevention.

Forty percent of drivers who were fatally injured in an accident in 2013 tested positive for drugs, a share almost equal to the share of fatally injured drivers who tested positive for alcohol. In a recent roadside survey by the National Highway Traffic Safety Administration, 22 percent of drivers tested positive for a drug or medication.

The report, prepared by the GHSA and the Foundation for Advancing Alcohol Responsibility, says any drug can impair a person's ability to safely drive a vehicle. These drugs include illegal substances, prescription drugs, and over-the-counter medications.

"Every state must take steps to reduce drug-impaired driving, regardless of the legal status of marijuana," said Jonathan Adkins, executive director of the GHSA. "This is the first report to provide states and other stakeholders with the information they need. And we encourage NHTSA to issue guidance on best practices to prevent marijuana-impaired driving. We look to the federal government to take a leadership role in this issue similar to that of drunk driving and seat belt use."

"When drug use is combined with alcohol, the risk of a crash is increased dramatically," said Ralph Blackman, president and CEO of the Foundation for Advancing Alcohol Responsibility. "This is why it's so important to understand the scope of the problem and, more importantly, provide solutions to address it."

Effects

The GHSA says drugged driving is a more complex issue than drunk driving for a number of reasons. The NHTSA's Fatality Analysis Reporting System has codes for 430 different drugs, and the type of impairment and crash risk varies depending on the substance.

The report also notes that while drunk driving is considered socially irresponsible, drivers are often unaware of or indifferent to the effects of driving while under the influence of drugs. For example, respondents in previous surveys often said they don't believe that marijuana impairs their driving ability; some even thought the drug improved their driving skills.

Drivers may feel more confident in their ability to drive while under the influence of drugs because the absorption and metabolizing of a drug differs from person to person. Experiments have shown that different individuals require a wide range of drug concentrations to reach the same level of impairment. While alcohol-related impairment can be measured simply by blood-alcohol level, it is more difficult to determine the impairment caused by drug concentrations.

However, an analysis of several studies on drug-related crash risk between 1976 and 2011 found that certain substances are much more likely to cause a driver to get into an accident. Marijuana resulted in a slightly elevated but still significantly higher crash risk. The NHTSA determined that a driver under the influence of marijuana has a 25 percent higher chance of getting into an accident than a sober driver.

Cocaine and opioids resulted in a medium elevated risk. Amphetamines or multiple drugs resulted in a highly increased crash risk, while combining alcohol with drugs resulted in the highest risk.

Of the 62.6 percent of fatally injured drivers included in the FARS reporting who were tested for drugs in 2013, 34.7 percent tested positive for marijuana. A total of 30.3 percent had a drug that was included in the FARS drug list, 9.7 percent tested positive for methamphetamine, and 57.3 percent did not have any drugs in their system.

Recommendations

The GHSA says informing drivers about the risks of drugged driving is an important step to take in reducing this behavior. The organization suggests that agencies can analyze data in their own states, determine which audiences to address, and find out the best ways to deliver information on the subject.

While driving under the influence of drugs is illegal in all states, the report says stronger sanctions are needed to deter this behavior. It suggests zero tolerance policies for illegal drugs and drivers under the age of 21 who use drugs. In states where recreational marijuana use is permitted, the GHSA suggests a "per se" law to set limits on THC levels.

The GHSA says police officers, prosecutors, and judges should all be trained on the subject of drugged driving. It also recommends that all drivers who are killed in crashes be tested for the presence of drugs, while drivers arrested for drugged driving should be tested to determine the concentration of drugs in their bodies. Drug treatment programs are recommended for those convicted of drugged driving.

In order to establish more data on drugged driving, the GHSA says drugged driving data should be kept separate from that related to drunk driving. The organization says states should also collect data to judge the effect of educational campaigns, law changes, and other initiatives.

In addition to the state level suggestions, the report says several actions should be taken on a federal level to combat drugged driving. These include a national drugged driving education campaign, standardized road testing policies and devices, and federal guidelines for data collection.

"While this report summarizes the research and data available, it also highlights how much remains unknown," said Hedlund. "For example, we still don't know with certainty how much of a specific drug will cause impairment or if such a relationship can even be defined. Many states do not have the data to measure their drug-impaired driving scope or characteristics. The recommendations in the report will help states refine and augment their efforts to detect and deter drug-impaired drivers."