"Compelling evidence in other states suggest racial disparities persist or have become worse after legalization and the opening of a licensed marijuana market, even while total marijuana-related criminal justice incidents have decreased.

"In Colorado, marijuana court filings decreased by 85% from 2010 to 2014 after legalizing marijuana in 2012. During the same time frame the rate of arrests for marijuana possession among African Americans/Blacks remained 2.4 times higher compared to the arrest rate for whites. The disparities for African American/Blacks were even larger for arrests for marijuana cultivation (2.5 times the arrest rate for whites) and distribution of marijuana (5.4 times the arrest rate for whites).13

"Results from Oregon are consistent with findings in Colorado. The Oregon Public Health Division examined changes in the age-adjusted rates of marijuana arrests by racial groups.14 The age adjusted rate of marijuana arrests for African Americans/Blacks was 2 to 3 times the rate of whites during 2010–2014. Oregon legalized marijuana in 2014 and in the following year the disparity between African Americans/Blacks and whites persisted. Specifically, the rate of arrest was 77% higher among African Americans/Blacks in 2015 when compared to whites.

"Preliminary results suggest that legalization of marijuana for adults has greatly reduced the number of people arrested and convicted for marijuana-related crimes, yet racial disparities persist in Washington and in other states. Other factors may contribute to sustaining the racial disparities, such as over-policing in low-income neighborhoods, racial profiling, and other racially biased police practices.15 These inequitable practices may minimize the potential positive impacts of I-502 and marijuana legalization on all communities."

Source

Firth C. Marijuana Legalization in Washington State: Monitoring the Impact on Racial Disparities in Criminal Justice. Alcohol & Drug Abuse Institute, University of Washington, June 2018.