Marijuana is often used as a tool by police officers to search your car.
In many cases, the mere odor of weed serves as probable cause to pull you over and rifle through your belongings. States that have decriminalized it are still grappling with the legality of using marijuana for warrantless searches.
In the case of Philando Castile, who was shot to death by a Minnesota police officer during a traffic stop last year, we saw the devastating effects the smell of marijuana can have on an officer's perception of motorists. Though marijuana is decriminalized to some degree in the state, St. Anthony Police Officer Jeronimo Yanez would later tell investigators that he thought he was in danger because he smelled weed:
"As he was pulling out his hand I thought I was gonna die, and I thought if he has the guts and the audacity to smoke marijuana in front of the five-year-old girl, and risk her lungs and risk her life by giving her secondhand smoke ... then what care does he give about me?"
It may come as no surprise, then, that states that have legalized marijuana are seeing a dramatic decline in warrantless searches.
NBC News did a deep dive into reports by the Stanford Open Policing Project, which collected data on 60 million traffic stops and searches by highway patrol officers in 22 states.
In Washington state and Colorado, NBC News found that searches were cut by more than 50 percent within months of legalization. Washington state saw a 50 percent reduction within three months, while Colorado saw a more gradual reduction, but searches still dropped by more than 50 percent within a year.
Legalization can lead not only to fewer warrantless searches, but an increase in the public's trust of officers, the site found.
That said, full legalization may not have helped Castile. The report found that ethnic minorities are still stopped and searched disproportionately to white drivers in states where weed is legal.
Marijuana prohibition has always been racist. HuffPost's Nick Wing reported in 2014:
According to a 2013 study by the American Civil Liberties Union, blacks across the nation were nearly four times more likely than whites to be arrested on charges of marijuana possession in 2010, despite data that suggested they use the drug at about the same rate. In some states, blacks were up to six times more likely to be arrested. This disparity isn't new, and plays into broader arrest data: A study published in the journal Crime & Delinquency this month found that by the age of 23, nearly 50 percent of black males have been arrested, compared to 44 percent of Hispanic males and 38 percent of white males.
Data collected by the Stanford Open Policing Project implies that not much has changed today.