[Pearls Before Swine]

His big point is that the local police have a strong financial incentive to arrest, ticket, and otherwise harass the city’s black residents for minor offenses, because that’s how the department funds its budget.

It's at least as bad for whites, who in addition to speed traps, have to worry about higher-ticket assessments, like civil asset forfeiture.

[Kirkwood]

At 2/3rds of the population, blacks are always going to be proportionally stopped more often than whites. The only way to avoid this is to have no police force at all.