Legal Weed, Riskier Roads? How Cannabis Legalization Is Complicating Traffic Safety

As recreational marijuana laws spread across the U.S., road safety experts are sounding the alarm. According to a study compiled by The Texas Law Dog, traffic fatalities and serious crashes are on the rise in states that have legalized cannabis for adult use. The numbers point to a complex public safety issue one that mixes evolving drug policy with changing driver behavior and insufficient enforcement tools.

The Numbers Behind the Trend

In 2011, no states had legalized recreational cannabis. By April 2025, that number had surged to 25. Over the same time period, car crash statistics began to shift. The Texas Law Dog study highlights a nationwide 6% rise in car crashes and a 4% increase in fatal accidents linked to marijuana legalization.

States like California, Colorado, Nevada, Oregon, and Washington among the first to legalize have all reported noticeable increases in traffic fatalities. In Colorado, fatal crashes rose by 16%. Oregon saw a 22% uptick, while Alaska and California followed with increases of 20% and 14%, respectively.

A Nation of Cannabis Users—and Drivers

Cannabis use has skyrocketed alongside legalization. In 2002, about 11% of Americans aged 12 or older reported marijuana use. By 2019, that figure reached 18%—amounting to more than 48 million users. Notably, many users are also drivers. The study found that 85% of marijuana users admitted to driving the same day they used the drug, with 53% doing so within an hour.

These behaviors are particularly concerning because cannabis is known to impair reaction time, coordination, and decision-making. Research shows that during the COVID-19 pandemic, cannabis-involved fatal crashes actually surpassed alcohol-involved fatalities for the first time 33% versus 29%.

Mixing Substances: A New Layer of Risk

The risks compound when cannabis is used alongside alcohol or other substances. Before the pandemic, 18% of drivers in fatal crashes tested positive for multiple substances. After the pandemic began, that number jumped to 25%.

This poly-substance use creates enforcement challenges and makes it harder for investigators to isolate marijuana’s role in accidents. It also complicates public health messaging around impaired driving, which has historically focused on alcohol.

Legal States, Higher Crash Rates

The link between cannabis policy and traffic safety becomes even clearer when comparing states. According to the study, states that legalized recreational marijuana saw a 4–6% rise in crashes resulting in death or injury. Conversely, states with only medical cannabis laws actually saw an 8–11% decrease in fatal crashes.

That disparity suggests recreational access has a direct impact on road safety outcomes. Whether it’s due to frequency of use, public perception, or policy enforcement, the data points toward real consequences.

Public Perception and Enforcement Gaps

Despite evidence of risk, many cannabis users remain unconcerned about getting caught. Nearly 30% of respondents said they believed police would not be able to tell they were under the influence. Only 26% thought they could be reliably detected.

Yet, paradoxically, users also acknowledge the danger. Seventy percent said it would be “highly dangerous” to drive within an hour of consuming marijuana, and 93% said their friends or family would disapprove of such behavior.

This disconnects between personal awareness and actual behavior highlights an urgent need for better public education. If users understand the risk but still choose to drive, enforcement alone won’t solve the problem.

State-by-State Disparities Add to Confusion

Complicating the picture further are the patchwork laws across the country. Some states, like Alaska, limit recreational possession to one ounce but allow medical users to hold 2.5 ounces every two weeks. California permits up to eight ounces for medical use. Others, like Idaho and Nebraska, prohibit all forms of cannabis.

This inconsistency contributes to public confusion and enforcement challenges, especially for drivers crossing state lines. Without uniform standards, it becomes harder to regulate or anticipate behavior on the road.

A Call for Action: What Can Be Done?

The findings in The Texas Law Dog’s report point to a growing need for state and local governments to reassess how they approach cannabis-impaired driving. Options could include:

• Stricter penalties for driving under the influence of marijuana

• Expanded roadside testing capabilities

• Uniform THC limits for drivers across all states

• Public education campaigns targeting high-risk groups

• Funding for research into cannabis impairment and driving

Additionally, states considering legalization may need to build traffic safety frameworks in tandem with policy changes. That means training law enforcement, updating DUI laws, and launching proactive public awareness efforts before legalization takes effect.

Conclusion: A Complex but Addressable Threat

As more states legalize marijuana, traffic safety is becoming an increasingly urgent issue. The Texas Law Dog study makes a compelling case: cannabis use is correlated with higher crash rates, especially where recreational access is widespread.

Recognizing the risk is the first step. The next is acting on it through data-backed policies, improved enforcement, and informed public discourse. Until then, the road ahead may continue to get more dangerous.