The NYTimes has a good piece on revenue driven policing:
Many municipalities across the country rely heavily on ticket revenue and court fees to pay for government services, and some maintain outsize police departments to help generate that money, according to a review of hundreds of municipal audit reports, town budgets, court files and state highway records.
…In Bratenahl, Ohio, the town government is so dependent on traffic enforcement that the police chief castigated his officers as “badge-wearing slugs” in an email when a downturn in ticket writing jeopardized raises. Ticket revenue helped finance sheriff’s equipment in Amherst County, Va.; a “peace officers annuity and benefit fund” in Doraville, Ga.; and police training in Connecticut, Oklahoma and South Carolina.
Revenue driven policing can be most extreme when the people you are ticketing are not voters.
Newburgh Heights, a frayed industrial village of about a half square mile with 2,000 residents just south of Cleveland, doggedly monitors traffic on the short stretch of Interstate 77 that passes through.
…All told, revenue from traffic citations, which typically accounts for more than half the town’s budget, totaled $3 million in 2019.
My paper, To Serve and Collect (with Mike Makowsky and Thomas Stratmann) shows that there is a notable increase in revenue generating arrests when local governments are facing a deficit. More from Makowsky in this thread.