77% Drop in Cannabis Seizures After Legalization—But Bias Persists

by Jon Scaccia April 30, 2025

Let’s say you’re driving home, windows cracked, and your car smells… herbal. In states where cannabis is still illegal, that scent alone might be enough for the police to search your vehicle. But what happens when cannabis becomes legal—and that excuse disappears?

A new study used data from over 3.3 million drug seizure events across 16 U.S. states to explore what really happens to policing when cannabis is legalized. Spoiler: cannabis-related drug seizures drop dramatically. But while this lightens the law enforcement load, it doesn’t erase deep-rooted racial disparities in who gets searched—or why.

What the Study Looked At

Researchers dug into six years of data from the National Incident-Based Reporting System (NIBRS), a national law enforcement database that tracks drug seizure incidents. They compared 16 states—some that legalized cannabis for adult use between 2017 and 2022, and others that didn’t.

They weren’t just counting joints and baggies. They wanted to know:

• Does legalizing cannabis reduce drug seizures overall?
• What happens to seizures of other drugs (like opioids or meth)?
• Does legalization impact racial disparities—especially between Black and white individuals?

The Big Drop: Cannabis Seizures Fell 77%

Once cannabis was legalized in a state, overall drug seizures dropped by about 30%—but almost all of that came from cannabis itself. Seizures involving only cannabis dropped a whopping 77%.

This isn’t too surprising. If a drug becomes legal, police can’t seize it as often. But the story gets more complicated when you look beyond cannabis.

Other Drug Seizures? Mostly Unchanged

Despite hopes that legalization would also reduce police stops and seizures of other substances—since the smell of cannabis is no longer enough to justify a search—the study found little change.

In fact, methamphetamine seizures that didn’t involve cannabis increased by 54%. That could suggest police simply shifted their focus from cannabis to other drugs, rather than scaling back enforcement overall.

Racial Disparities Persist—Except Slightly for Cannabis

Before legalization, Black individuals were 3.7 times more likely than white individuals to have drugs seized by police. Legalizing cannabis led to a 17% drop in that Black-white disparity—but only for cannabis seizures.

For other drugs like cocaine, meth, or opioids? Racial disparities stayed stubbornly in place.

This echoes a troubling pattern seen in prior research: even when laws change, systemic bias in policing often endures.

So Why Does This Matter for Public Health?

It’s tempting to treat cannabis legalization as a win-win: less incarceration, less burden on law enforcement, and more tax revenue. But this study shows we can’t stop there.

Drug seizures—especially when they’re racially skewed—have real-world consequences. They can lead to criminal records, economic instability, and distrust between communities and law enforcement. And disruptions to drug supply chains (like from police seizures) have even been linked to spikes in fatal overdoses.

In short, cannabis policy is public health policy.

What Still Needs Work

While this study offers the clearest picture yet of how legalization affects police behavior, it also shows how uneven implementation can be. Not all states treat cannabis odor the same. Some still allow it as probable cause for a search. Others, like Connecticut, have banned that practice outright. But how these policies are enforced in the real world remains murky.

More research is needed to understand how law enforcement reallocates time and resources post-legalization—and whether communities truly feel the impact.

What’s Next?

The federal government is currently considering “down-scheduling” cannabis, a major shift that could echo throughout police departments nationwide. If that happens, studies like this will be critical to understanding how law enforcement—and the communities they serve—adapt.

For now, the takeaway is clear: Legalizing cannabis does reduce drug seizures. But it doesn’t magically fix systemic racism in policing. True reform takes more than a new law—it takes intentional action to dismantle old habits.

Join the Conversation

• Have police practices changed in your community since cannabis was legalized?
• Do you think legalization is enough to address racial disparities in drug enforcement?
• What else should policymakers consider to ensure equitable policing?

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