More people tested positive for marijuana than alcohol in a roadside survey of California drivers pulled over by police on weekend nights.

That occurred five years ago — four years before voters legalized recreational use of marijuana in California.

With local and state government agencies gearing up to license growers, processors and retailers, at least those willing to abandon the black market, it’s a near certainty that even more people will be getting behind the wheel after smoking a joint or eating a marijuana-infused treat.

You can count on this too: more people will be hurt or killed in accidents caused by drivers under the influence of marijuana.

In Colorado, where recreational use has been legal since 2013, the number of marijuana-related auto fatalities has more than doubled, according to an analysis by the Denver Post of coroner’s reports and other state and federal data.

Even more disturbing, the trend is accelerating.

Colorado drivers tested positive for marijuana in about 10 percent of all fatal crashes in 2013, the Post reported. Last year, 20 percent of drivers tested positive. Over the same four-year period, the number of fatal accidents jumped from 47 to 115, a 145 percent increase.

The total is probably higher because Colorado coroners aren’t required to test deceased drivers for marijuana, and not all of them do. Many police agencies don’t bother with marijuana tests for surviving drivers whose blood-alcohol level exceeds the legal limit.

However, 69 percent of the drivers who tested positive for marijuana after fatal accidents in 2016 had no alcohol in their systems. And 60 percent were found to have THC, the psychoactive compound in marijuana, in their blood, indicating use within a few hours.

Driving under the influence of drugs, including marijuana, is illegal. But surveys show that many people believe it’s less dangerous than driving under the influence of alcohol. It isn’t.

Unfortunately, there isn’t a standard for marijuana analogous to the blood-alcohol content limit of 0.08 percent that most states, including California, have adopted. Neither is there a test comparable to the breath test used to detect alcohol intoxication. Not yet anyway.

California took a small step this week to deter motorists from using marijuana.

Senate Bill 65 prohibits smoking or eating marijuana by drivers or passengers in a motor vehicle. A violation carries a $70 fine. The bill by state Sen. Jerry Hill, D-San Mateo, parallels existing law against drinking alcohol or having an open container in a vehicle.

Hill’s legislation passed through four committees as well as the full Senate and Assembly without a single dissenting vote. Gov. Jerry Brown should sign it into law.

Traffic fatalities are increasing sharply in the United States, despite a growing number of safety features on new vehicles. Cellphones and other distractions are a primary cause. Despite decades of warnings and ever-stiffer penalties, drunken driving remains a serious problem and the cause of too many tragedies. Marijuana, as the Colorado data show, is too. And it’s likely to get worse.