Marijuana plants ready for harvest in Colorado.

(AP Photo/File)

The Colorado State Patrol now searches far fewer drivers after traffic stops than it did before recreational marijuana became legal, according to a recent study by Stanford University. But the numbers also show that, during the same time frame, blacks and Hispanics were stopped and searched more than whites. In fact, the gap between searches of whites and minorities grew. 

The question is, why? We asked Justin George of the Marshall Project, a nonprofit news organization that specializes in criminal justice issues. His organization and the Center for Investigative reporting parsed the findings. Below we have a brief summary of key points in the conversation, and some related links.

Why the Marshall Project paid so much attention to Colorado:

The Stanford study was a national look at police searches, the Marshall Project and its partner, the Center for Investigative Reporting, decided to zero in on Colorado and Washington because of legalization. Because these two states have the longest history with legalization they were the obvious ones to study.

How the data looks for Colorado:

Stanford, the Marshall Project and CIR analyzed 2.6 million Colorado State Patrol traffic stops between Jan. 1, 2010 and June 1, 2016. The stops were divided almost evenly before Dec. 12, 2012, but then:

  • Looking at drivers of all ages, the rate for whites per 1,000 stops went down 61 percent, Hispanics 56 percent, blacks 51 percent
  • Before legalization there were 4.6 searches of cars driven by whites for every 1,000 traffic stops. That dropped to 1.78 after legalization.
  • Before legalization there were 10.47 searches of Hispanic-driven cars for every 1,000 traffic stops, compared to 4.65 after legalization.
  • Before legalization there were 10.6 searches of black-driven cars for every 1,000 stops, compared to 5.19 after legalization.

The rate of searches for all ethnic groups went down fastest for whites:

  • Blacks were 2.1 times more likely to be searched than whites before legalization, Hispanics were 2.5 times more likely. After legalization, both blacks and Hispanics were 2.6 times more likely to be searched than whites.

The State Patrol isn't ready to draw conclusions:

"I think that it is too early to say that marijuana is the cause for a reduction in searches," said spokesman Sgt. Rob Madden, after we reached out for comment."The data that we are collecting and the time period that we have been collecting the data does not allow us to come back with anything that is a definitive based on one addition or subtraction of state law."