New federal statistics show that the rate of drunken driving in the United States fell to a 13-year low in 2014, the latest year for which data is available.
The rate of driving under the influence of illicit drugs has not changed meaningfully in recent years but remains slightly lower than it was in 2008 and 2009 at the start of the Obama administration.
In 2014, as part of the National Survey on Drug Use and Health, 11.1 percent of Americans 16 or older told federal interviewers they had driven under the influence of alcohol in the past year. There's a certain amount of squishiness about these numbers, given that they're self-reported. Respondents may have different thresholds for what they think constitutes "impairment" or they may be reluctant to report what is essentially illegal behavior in an interview.
But the survey has been administered with the same methodology since 2002, meaning it provides a particularly useful measure of drunk and drugged driving trends over time. And the findings are fairly unequivocal: In 2002, 15.3 percent of Americans said they drove drunk, 5 percent said they drove under the influence of one or more illicit drugs, and 3.3 percent said they drove under the influence of both simultaneously. By 2014, those numbers had fallen to 11.1 percent, 4.1 percent and 2.4 percent, respectively.
Experts caution that while the trend is heading in the right direction, there's still a lot of work to be done. "Although it is heartening to see a downward trend in levels of driving under the influence of alcohol, it still kills thousands of people each year and shatters the lives of friends and loved ones left behind," said Frances Harding, director of the Center for Substance Abuse Prevention at the Substance Abuse and Mental Health Services Administration, the agency that produces the survey.
In 2015, for instance, 10,265 people were killed in crashes involving alcohol impaired vehicle drivers, according to the National Highway Traffic Safety Administration. That's an increase of more than 300 fatalities from the prior year, when 9,943 people were killed in drunken driving incidents.
But American drivers logged many more vehicle miles in 2015, traveling 3.148 trillion miles in 2015, up from 3.026 trillion in 2014. Expressed as a function of vehicle miles traveled - the rate policymakers use to measure the prevalence of drunken driving deaths - alcohol-impaired driving fatalities actually fell from .33 deaths per 1 million miles in 2014 to .32 deaths per million miles in 2015, at least a 10-year low.
The SAMHSA survey showed that young adults - particularly men ages 21 to 25 - had by far the highest impaired driving rates. More than 1 in 5 men ages 21 to 25 drove drunk in 2014, nearly 1 in 7 drove under the influence of other drugs, and roughly 1 in 12 drove while simultaneously drunk and drugged.
On the other hand, young adults have also seen the greatest reductions in drunken driving prevalence over the past 13 years. Since 2002, the drunken driving rate fell by fewer than three percentage points among drivers age 26 and older. But the rate among drivers ages 21 to 25 dropped by more than 10 percentage points. And the prevalence among the youngest drivers, ages 16 to 20, fell by more than half.
There's no single factor driving the decline in drunken driving rates. The Centers for Disease Control and Prevention credits interventions like strong drunken driving laws, public awareness campaigns, and ignition interlock systems that don't allow drunk drivers to start cars.
Some states are experimenting with innovative programs that essentially take away the right to drink alcohol, period, for people convicted of certain alcohol-related crimes. There's also evidence that ride-sharing services like Uber can reduce drunken driving rates, although not all researchers agree on this.
"We must strive to save lives by reducing this public health threat through education, prevention, and all other possible measures," Harding said.