Fatal drug-related car accidents are outpacing deadly alcohol-related crashes. According to a new report released by the Governor’s Highway Safety Association, there’s been a significant number of drivers who have been killed while driving under the influence of drugs.

In 2016, up to 38% of drivers killed in an accident were under the influence of alcohol compared to the 44% of drivers under the influence of drugs. This is a major jump from the 28% of drug-related fatal accidents in 2006.

“There are more prescriptions of drugs than ever before,” said Russ Martin, the director for the Governor’s Highway Safety Association. “And we are in the midst of an opioid crisis.”

More than half of the drivers killed in drug-related accidents tested positive for opioids, marijuana, or a combination of the two. With more states legalizing marijuana, the increase in accidents may be related to the difficulty of identifying and testing drivers for drugs.

CBS reports one incident where a police officer let a driver go after being involved in a fender bender. The driver, who was on sedatives and painkillers, showed no signs of impairment and caused a deadly accident just 19 minutes later.

“Right now, we don’t have a nationally agreed upon way to test drivers for drug impairment similar to a breathalyzer or blood test for alcohol,” Martin said.

The slow reaction time of drug and alcohol impairments, when combined with common distractions and road obstructions, can be incredibly dangerous.

For instance, over the course of a four-year study by AAA, two-thirds of the 200,000 crashes that took place were the result of improperly secured cargo.

Additionally, 66% of drivers let themselves be distracted when they’re driving through a parking lot.

Even the vehicles themselves are a common factor in motor vehicle accidents. Up to 85% of vehicles on the road need some kind of repair or maintenance. And only 89% of lubrication professionals say they consider an oil’s viscosity index when they buy a lubricant.

These common problems and distractions when paired with slow reaction time, impaired judgment, and blurred vision make driving while under the influence of drugs life-threatening. Yet there were more than 20,000 charges for driving under the influence of drugs in 2017 in Pennsylvania alone.

To combat the difficulty of identifying impaired drivers, many police departments across the U.S. are training their officers to better recognize potential signs of drug use.

This training is especially important as we near what law enforcement calls the “100 Deadliest Days” for car accidents. According to Rhinelander Police Chief Lloyd Gauthier, the days between Memorial Day and Labor Day are the worst for car accidents because of the increase in drivers on the road.

A new AAA report says that there’s a 14% higher rate of deadly crashes during the summer months than any other time of year.

More families are on vacation and more teenagers are on the road. Up to 10 people in the U.S. are killed during the summer months by teen drivers every year.

The biggest factors in deadly crashes involving teenagers, Gauthier says, are phones, friends, and other distractions. “Just be alert and conscious of what’s going on in front of you,” Gauthier said.