Lesser Evil or More Dangerous Driving? Jerry Study Finds DUI Rates Double in States with Legal Recreational Marijuana

Ben Guess
Jan 19, 2022 · 7 min read
Key Insights:
  • In states where recreational marijuana use is legal, the DUI rate is nearly double that of states where it’s illegal.
  • The increased DUI rate may be due to mixing recreational substances, or “cross-fading,” vs. the use of recreational marijuana alone.
  • In states where recreational marijuana use is illegal, open container violation rates are double those of states where it’s legalized or decriminalized.
  • The average careless driving violation rate in states where recreational marijuana use is illegal is 44% higher than in states where it’s legalized or decriminalized.
There is an ongoing battle over legalizing marijuana in many states. New analysis from Jerry found that recreational marijuana legalization correlates with higher DUI rates but lower open container and careless driving violations. (We define DUI as a citation given when a driver is too impaired by a substance to drive.) The average DUI rate in states where recreational marijuana use is legalized or decriminalized is nearly double that of states where it remains illegal. While the overall rate of all violations rate is 21% in states where recreational marijuana is illegal, the average violation rate across states where it’s been legalized or decriminalized is 27% — a 6% difference, or 109,259 more violations per year.
 While the DUI rate was higher in states where recreational marijuana use is legalized or decriminalized, specific violations decreased. Open container violation rates are twice as high in states where recreational marijuana use is illegal. Similarly, the average careless driving rate is about 44% higher in states where recreational marijuana is legalized or decriminalized. States where recreational marijuana is legal might have more citizens using marijuana and driving in these states, but they also have fewer careless drivers.  

Rates of Violations where Recreational Marijuana is Permitted vs. Illegal

Type of StateOverall Violations RateDUI RateOpen Container RateCareless Driving Rate
__Recreational Marijuana Legalized/Decriminalized__27.05%*5.32%0.30%4.28%
__Recreational Marijuana Illegal__21.16%2.88%0.62%6.15%

Violation Rates

Overall violation rates are higher in states where recreational marijuana is either decriminalized or legalized, with the highest rate in states where it’s specifically legalized. This means that the data correlates permitting recreational marijuana with higher rates of driving violations.
This may be due to the difference between legalization and decriminalization. Decriminalization doesn’t apply any specific laws to recreational marijuana usage. By decriminalizing marijuana use, states are simply confirming that people won’t face legal repercussions for recreational marijuana use or possession. Those possessing or using a small amount (which differs by state) for the first time will be cited, instead of facing jail time or a criminal record. 
Legalization involves specific laws regulating recreational marijuana usage, including THC limits or impairment limits for drivers. (THC is the psychoactive component of cannabis that produces the feeling of being high and contributes to impairment.) In states where it’s legalized, the standards for appropriate recreational marijuana use are much higher than in states where it’s simply decriminalized. 

Rate of DUIs

When someone receives a DUI for drunk driving, their blood alcohol content (or BAC) exceeds the limit set by the state. When the substance is marijuana, either the level of THC in a driver’s blood exceeds the state limit — usually set at 5 nanograms of THC per milliliter of blood (5 ng/ml) — or they meet the state’s criteria for impairment, which generally include erratic driving and slurred speech. State limits for THC vary from zero tolerance, meaning no level of THC while driving is legal, to 5 ng/ml. Several states distribute DUIs for driving while high based on general impairment and behavior rather than a specific amount of THC.
The data revealed a significant correlation between DUIs and permitting recreational marijuana use. The average DUI rate in states where recreational marijuana is illegal is 2.88%, nearly half the average DUI rate in states where recreational marijuana use is permitted at 5.32%. 
Part of this is due to issues of legalization — when there are more laws to break, people are more likely to get violations. However, the DUI rate in states where recreational marijuana use is permitted is still significantly higher than the rate in states where it’s illegal. This means that there is a strong correlation between recreational marijuana and a higher DUI rate.
Still, drivers in states where recreational marijuana is legal or decriminalized are not using only marijuana. A study done by AAA and reported by Live Science found that while the percentage of fatal crashes involving Washington state drivers with THC in their blood jumped from 8.3% to 17% after marijuana was legalized, two-thirds of that 17% also had another drug or alcohol in their system. A study from the National Highway Traffic Safety Administration found marijuana isn’t likely to severely impair drivers, and compared it to driving with a BAC of 0.01 to 0.05, which is legal in all states. Recreational marijuana use may be correlated with higher rates of DUIs, but additional drug or alcohol usage might contribute to these DUI rates more than marijuana alone.

Open Container Violations

States that permit recreational marijuana use have an open container violation rate of 0.30% — half the rate of states that do not permit recreational marijuana, at 0.62%.
This indicates that if marijuana is a recreational option, it could take the place of drinking. While it’s always a bad and life-threatening decision to drive while impaired, a study by the National Center for Biotechnology Information suggests that alcohol can impair drivers more reliably than marijuana. Marijuana is potentially a “lesser evil” when it comes to methods of driving impairment, especially since it correlates with fewer open containers on the road.

Careless Driving Violations

The careless driving rate in states where recreational marijuana use is illegal is 6.15% — a 44% increase from the rate in states where it’s permitted (4.28%).
This may be due to drivers choosing marijuana over alcohol. Research shows that Marijuana only impairs one’s driving ability to the equivalent of 0.01-0.05 BAC, and New Jersey, Pennsylvania, and Rhode Island all tie for the strictest BAC state limit at a BAC of 0.10—twice as high as marijuana’s equivalent at 5 ng/ml. Tipsy drivers under the BAC limit might be more impaired than high drivers, and therefore, more careless. 
With marijuana available as a recreational option, drivers may be choosing to drive under the influence of marijuana instead of alcohol. This lowers their risk of careless driving as a result. Mixing different types of recreational substances, or “cross-fading,” is still a dangerous possibility in states with legal recreational marijuana. However, this data does suggest a correlation between recreational marijuana legalization or decriminalization and fewer instances of careless driving.
Average U.S. Rates of Driving Violations

Conclusion

While the data found a correlation between legalized or decriminalized recreational marijuana use and both increases and decreases in driving violations, there are several other factors — driving laws and types of DUIs, for example — needed to determine a causal relationship. Still, the correlation is a stark one. 
It is never a good idea to drive while under the influence of any substance. That said, research does suggest that marijuana, when used alone, may be less impairing than alcohol. Ultimately, it’s up to states and their constituents to decide whether or not to allow recreational marijuana use. But it’s important to consider all the factors involved — such as whether permitting recreational marijuana use will keep drivers more or less safe out on the road.

Methodology

This study used almost 1 million points of Jerry customer data. States where recreational marijuana use is illegal include: Alabama, Arkansas, Florida, Georgia, Idaho, Iowa, Indiana, Kansas, Kentucky, Oklahoma, Pennsylvania, Tennessee, Texas, South Carolina, South Dakota, Utah, Wisconsin, West Virginia, and Wyoming. All other states decriminalized or legalized the recreational use of marijuana.

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