More drivers were killed while under the influence of drugs than alcohol, said a report by the Governors Highway Safety Association that shows the increasing prevalence of drug use on the road.

The report found that in 2016, 44 percent of drivers killed were tested positive for drugs, an increase from 28 percent in 2006. This figure surpassed the percentage of drivers killed who tested positive for alcohol, which was 38 percent in 2016. This declined slightly from 41 percent in 2006.

Among the drugs that were found in fatally-injured drivers, the two most prevalent were marijuana and opioids. Forty-one percent of the drug-positive drivers tested positive for marijuana use.

“Marijuana use is rapidly becoming normalized, with recreational marijuana legal in 9 states and the District of Columbia and medical marijuana approved in 29 states and the District of Columbia,” the report stated. “Opioid addiction and opioid overdose deaths have become a national crisis, with overdoses producing an estimated 115 deaths daily.”

The report further explained causes behind increasing cannabis use on the road: “Marijuana is no longer just smoked, it’s vaped, eaten, drunk, dabbed, chewed, or wiped, often in much higher concentrations than traditional smoked joints. Marijuana affects driving-related skills but its effect on crash risk is uncertain.”