Yes, economic status has a greater correlation with petty crime and contact with police (even when innocent of any crime), a point which is stressed much more heavily in the rest of the book. This is not incidental. It is intentional, and has been since the origin of American police forces.
Discussion
What evidence and motivation is there for this intent?
I don't have the exact facts and figures off the top of my head. I highly suggest you give the book a read. The chapter on policing and homelessness elaborates this quite well. Many American police forces were created in the early days to control and banish the homeless and very poor, often newly arrived immigrants from eastern and southern Europe, by criminalizing everyday, normal activities.