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Drugs Appear to Be a Factor in Rising Impaired Driving Crashes

States are boosting oral fluid testing and toughening laws on ignition interlocks and impaired drivers who cause fatalities.

By Mark Wolf  |  December 11, 2023

Drunken driving is one thing that makes driving increasingly dangerous. Combined with drug use, it can be quite another.

The latest available statistics reported that of the nearly 43,000 people killed in motor vehicle crashes in 2021, 31% of those fatalities involved alcohol-impaired drivers—a 14% increase from 2020—and 18% involved a driver who tested positive for two or more impairing drugs

“That’s pretty sobering and a real crisis on our roadways,” Kelly Poulsen, senior vice president of government relations for, told a session of NCSL’s Base Camp on impaired driving.

Annie Kitch, a senior policy specialist at NCSL, says driving under the influence of drugs appears to be a factor in the increasing number of impaired driving crashes.

“One thing that’s critical to point out is that it is difficult to track drug-impaired driving because we don’t have enough data regarding drug prevalence in impaired drivers,” she says. That’s because impaired drivers are often tested only for alcohol, not drugs.

Interventions to Combat Impaired Driving

“More states are exploring roadside oral fluid testing as an alternative to identifying drug presence in drivers,” Kitch says. “Most of us are familiar with roadside breath testing for alcohol with a breathalyzer. But similarly, roadside oral fluid testing involves a law enforcement officer who observes signs of impairment.”

Fluid testing involves using a cotton swab or other absorbent collector to take a mouth fluid sample. Analyzing the sample generally takes a few minutes. A positive result can help establish probable cause in a court case. However, the test only measures the presence of a drug, not the amount.

Even though 27 states have laws authorizing some form of oral fluid screening, only Alabama and Indiana currently have active programs, Kitch says. Other states are studying whether oral fluid tests can be a sustainable method to police cannabis in DUIs.

Other interventions to combat drunken driving include ignition interlocks, which are devices installed in a vehicle to prevent it from starting if a certain amount of alcohol is detected on a driver’s breath.

“Studies are currently showing that these devices can reduce DUI recidivism by about 70%,” Kitch says.

The devices have stopped more than 20 million attempts to drive drunk after alcohol consumption over the last decade, according to the Coalition of Ignition Interlock Manufacturers.

“However, despite their noted benefits, and the fact that every state has an ignition interlock law in some form, the industry is seeing that there are still relatively low installation rates,” Kitch says. “States are really working to revise these laws to ensure that the individuals who may qualify to install these devices in their vehicles are installing them in order to help keep the roads safer and use the devices properly.”

More states are passing laws that require all offenders, including first-time offenders, to install an ignition interlock, she says, adding that some states are enacting or considering legislation requiring impaired drivers convicted of vehicular homicide to pay child support for their victims’ surviving children.

“This is legislation that we saw take off like wildfire in 2023,” with at least 19 states considering bills requiring impaired drivers to pay child support if a parent is killed in a wreck, Kitch says. Tennessee was the first to enact such legislation in 2022, followed by Kentucky, Maine and Texas in 2023.

“We are eager to see if it continues in 2024 throughout the bulk of the legislative sessions,” she says.

Mark Wolf is a senior editor at NCSL.

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