Drug policy experts often say that the health risks of marijuana use are relatively minor compared to the steep costs of marijuana enforcement: expensive policing, disrupted lives, violence and even death.

Law enforcement agencies, however, have often been at the forefront of opposition to marijuana legalization. One reason is that the drug, with its pungent, long-lasting aroma, is relatively easy to detect in the course of a traffic stop or other routine interaction. It’s an ideal pretext for initiating a search that otherwise wouldn’t be justified — even if that search only turns up evidence of marijuana use and nothing more.

New data on traffic stops in Colorado and Washington underscore this point: After the states legalized pot, traffic searches declined sharply across the board. That’s according to the Open Policing Project at Stanford University, which has been analyzing public data of over 100 million traffic stops and searches since 2015.

In Colorado and Washington, traffic searches of black, Hispanic and white drivers fell significantly after legalization, according to the Open Policing Project’s analysis. That pattern didn’t hold for states where marijuana use remained illegal. [Read more at The Washington Post]