The city of Gretna, Louisiana, in the shadow of New Orleans, brings in more money through fines and related fees than some larger cities in the state. An investigation by WVUE-TV and ProPublica shows that much of that money comes from drivers who rack up multiple violations and hefty fines.

Defendants in Gretna’s mayor’s court, a unique justice system found only in Louisiana and Ohio, are charged with more violations — and face greater fines as a result — than those in seven other cities and towns we looked at. Many of those charges in Gretna are for nonmoving violations such as an expired license plate or vehicle inspection sticker.

And if a defendant misses a payment and doesn’t come to court to explain why, the court often adds a contempt charge, with an additional $150 fine. About half of Gretna’s cases over a three-year period included contempt charges.

A city representative said that officers charge people with violations only when they have probable cause, and that such fines deter motorists from breaking the law. A former New Orleans police chief, however, said cities can get people to follow the law without issuing lots of tickets.