Traffic fatalities involving an impaired driver have increased 44% since 2019, according to data released Thursday by the Colorado Department of Transportation.

There were 691 traffic deaths statewide in 2021, according to a news release.

Based on an analysis of 26,000 impaired driving cases filed in 2019, 45% of drivers tested positive for more than one substance, according to the state’s Division of Criminal Justice. The most common combination was alcohol with THC, followed by alcohol combined with other drugs.

“Colorado’s increase in traffic fatalities can be attributed to numerous causes, but impaired driving is a big one,” state Office of Transportation Safety Director Darrell Lingk said in a statement. “It’s our job to make sure people know that driving after combining alcohol and cannabis or other drugs is extremely dangerous.”

A report from AAA found drivers who said they used both marijuana and alcohol were more likely to report behaviors like speeding on residential streets, aggressive driving and texting while driving, according to the release.

“While there are safe ways to use both drugs, there is no safe way to drive under the influence of either, and those dangers are compounded when they’re combined,” Skyler McKinley, regional director of public affairs for AAA, said in a statement.