Marijuana is one of the most commonly used drugs in the United States, and its legalization in some states has sparked a debate about its effects on driving and road safety. In this article, we’ll analyze some current data about drivers operating under the influence of marijuana in California, one of the first states to legalize recreational use of the substance.

What does the law say?

According to California’s vehicle code, a driver is considered under the influence of a drug if their ability to drive safely is impaired by the consumption of any substance, whether legal or illegal, prescribed or not prescribed. This includes marijuana, which can harm the judgment, coordination, attention, and reaction time of drivers.

The law does not establish a specific limit of marijuana concentration in the blood to determine impairment. Still, it relies on evidence of the driver’s behavior and performance, field sobriety tests, and blood or urine analysis. Drivers caught driving under the influence of marijuana may face fines, license suspension, arrest, and even jail time, depending on the severity of the case and the offender’s history.

What does the data say?

According to a national survey conducted by the Centers for Disease Control and Prevention (CDC), 12 million young adults drove under the influence of marijuana in 2018, representing 4.7% of drivers in that age group.

In California, the Department of Public Safety Highways reported that 14% of drivers who died in traffic accidents in 2018 had marijuana in their system, representing a 9% increase since 2016 when recreational use of the drug was legalized.

Furthermore, a study from the University of California, Davis found that the number of drivers testing positive for marijuana in breathalyzer tests increased from 9% to 18% between 2017 and 2018, while the number of drivers testing positive for alcohol decreased from 38% to 31%.