Communities of color are over-policed. There's a huge racial divide in income, and crimes that tend to be committed by the poor (like shoplifting, loitering, and fare-evasion) are far more likely to be prosecuted than crimes committed by the wealthy (smoking some weed in your suburban living room, fudging your taxes a bit). The end result is that people of color are more likely to have an arrest record, even if they're just as likely to commit a crime as a white person.
For an example of this backed up by data, the NYPD stop-and-frisk program has always overwhelmingly focused on black and Latino people (almost 90% of all people stopped in some years), even though they make up only 15% of the population of some of the precincts involved AND white people were more individually likely to actually have an illegal weapon (the supposed reason for the stop-and-frisk program to exist).
