-It could be that some cops are assigned to densely white areas, while others must work in mostly black areas. This does not necessitate racism on behalf of the officers or management. (Perhaps it does in the overall local culture, as indicated by the self-segregation? To police an entire area, you must distribute resources to various portions of that area.) Racist cops might even prefer the dominant race of the area they work in, yet still mostly cite that dominant race, simply because there are so few disliked-race targets to look for.
-Certain violations cited to predominantly one race may simply indicate a reality in which people of that race break that law more often. This does not necessitate racist targeting on behalf of the officers. At that point, maybe a discussion about how seriously this law needs to be enforced should be had. Window tint? Dime bag of weed? Is that really such a big deal? (Ideally, these laws would just be removed. But politically this seems harder than using officer discretion.)