Driving Under the Influence

This article was originally published in our Fall 2020 print issue.

The legalization of marijuana continues to be a controversial issue following  the “war on drugs” in America. However, California has always been at the progressive forefront of passing cannabis laws. In 1996, California became the first state to legalize marijuana for medical usage, and it was the fifth state to legalize it for recreational use in 2016. Four years later, the state’s legal policies regarding drugged driving still remain inconclusive due to a lack of understanding on how legalization has impacted road safety. Recent studies provide insights concerning the correlation between DUIs, traffic accidents, and the legalization of recreational marijuana.

Marijuana, colloquially known as “weed” or “pot,” is a drug produced from the plant Cannabis sativa. It contains two major components: Cannabidiol (CBD) and Tetrahydrocannabinol (THC). CBD is the non-psychoactive chemical that is commonly used in medicine for treating anxiety, depression, insomnia, and chronic pain. On the other hand, THC is the main psychoactive compound in marijuana that produces the sensation of a “high.” According to Dr. Bruce Bagheri, a California cardiologist, “marijuana can essentially alter your level of consciousness and it affects how you drive.”

“Driving under the influence” (DUI) of any substance, including alcohol and marijuana, is considered a criminal offense. Marijuana is the most commonly found drug in the bloodstream of individuals involved in car accidents. Side effects from marijuana that could negatively impact driving are increased heart rate, problems with coordination, heightened anxiety, and slower reaction times, which mainly stem from the THC component. A 2012 study regarding “Cannabis Effects on Driving Skills,” conducted by Hartman and Huestis, proved that driving under the influence of marijuana results in an increase in driving speed, lane-weaving, position variability, and negatively impacts judgement and decision making.

When medical marijuana was legalized in California through Proposition 215 and Senate Bill 420, it established methods of regulation by mandating an identification card that verified medical marijuana patients before purchase. This legislation distinguished the  governmental agencies that were in charge of monitoring consumption. However, there was still backlash from political officials and the media about potential misuse of the drug due to gaps in legislation.

When Proposition 64 was on the ballot, intending to legalize  recreational marijuana, it furthered officials’ concerns. Organizations supporting legalization included the California Democratic Party, the California ACLU, the California NAACP, and Blacks in Law Enforcement of America. These supporters argued that marijuana should be decriminalized as it disproportionately affects people of color, would enable the government to  have better control over the market, and would result in less misuse of the drug. Additionally, they believed that tax revenue generated from the marijuana industry could be reinvested into improving rehabilitation programs and mental health facilities. Opponents of Proposition 64 included the California Republican Party, the California Police Chiefs Association, and the California Hospital Association. Opponents argued that legalization would actually enable further misuse of marijuana  by adolescents, result in an increase of public health emergencies, and facilitate sales in the black market. 

In terms of drugged driving, supporters argued that legalization would decrease DUIs and traffic accidents, while opponents argued that they would increase. Now that California is four years post-legalization, we can attempt to understand and examine exactly which claim the data supports. Unfortunately, there has been conflicting evidence. Studies conducted in states that have legalized marijuana since 2012, such as CO and WA, provide data that is available and applicable. In California, although marijuana was legalized in 2016, the practice of purchasing cannabis didn’t start until 2018, leading to a lack of sufficient data on DUIs and traffic accidents within that time frame.

A 2018 article titled, “Legalized Marijuana Linked to a Sharp Rise in Car Crashes” from NBC news, examined police reports and insurance claims from all states that have legalized recreational marijuana. They found that traffic accidents rose about 6% collectively in states that had legalized recreational marijuana, relative to states that had not. Additionally, a 2019 article by the Orange County Register indicated that “drug-related DUI cases nearly quadrupled in Los Angeles County” after comparing cases in 2017 to 2018, when retail sales of marijuana began in California. Contradictingly, a 2020 USA Today article demonstrated that, although California indicates an increase in drugged driving during fatal vehicle accidents, they have had 8.3% fewer traffic fatalities in 2018, compared to 2017. As reported, the data sends mixed messages;  some studies show an increase in traffic accidents correlating to  DUIs, while others show a decrease in California’s post-legalization era. What makes these findings even more ambiguous is that DUI data considers drugged driving incidents collectively, not exclusive to marijuana. They studied data in 2018, when retail sales of marijuana began, and compared it to previous years, but there’s no solid evidence we can utilize to confirm whether those results were caused after  legalization. 

So what can we conclude with the available data? Although there haven’t been many definitive results on DUIs in California post recreational legalization, the lack of sufficient data is most likely attributed to the inability to test and ambiguous police reporting of DUIs. Unlike alcohol or other illegal narcotics, marijuana accumulates in the body’s fat cells, which means that cannabis can stay in one’s bloodstream for an extended amount of time after the  effects wear out. Factors such as potency, gender, age, and method of use also  affect  how fast marijuana is metabolized. According to Dr. Marilyn Huestis, a toxicologist and expert on drug testing, “it generally takes women longer than men to filter marijuana out of the system and blood levels of THC can increase over time if people were physically active.”

As a result, there is no comparable tool, like a breathalyzer — which tests for blood alcohol content (BAC) — for obtaining immediate and definitive results for the presence of  marijuana in human systems. According to the Kraut Law Group, based in California, “the police must actually prove that the driver was under the influence of Marijuana and not merely rely on the results of chemical testing.” The only way to confirm driving under the influence of marijuana is to complete a blood or urine test. According to California driving laws, the principle of implied consent asserts that, “if lawfully arrested for a DUI, any person who drives a motor vehicle on the roads of California is deemed to have given their consent to chemical testing of their blood or urine for the purpose of determining drug contents.”

However, even if there was such an instrument similar to a breathalyzer, California doesn’t have a statute or “per se” limit on the amount of THC allowed in the body while driving. Other states that have legalized recreational marijuana have adopted limits ranging from 0.5 to 5 nanograms/milliliter. Furthermore, in California, when police file drugged driving reports, their documentation doesn’t distinguish between being under the influence of marijuana versus other illegal narcotic drugs. As a result, when drugged driving cases are analyzed specifically for marijuana usage, the data is misleading.

California has been a unique case in the controversy of legalizing recreational marijuana. Officials are  still in the beginning stages of analyzing data to confirm the impact legalization has on DUIs and traffic accidents. However, it is evident that Californian legislators must take action if we hope to see accurate and specific data collection  in the future. The state also needs to develop a more reliable  and efficient method for testing THC levels, adopt a “per se” limit for THC blood levels while driving, and give law enforcement the ability to distinguish DUIs of  marijuana exclusively.