As soon as someone parks, boot their car and make them pay $50 before they can LEAVE!
Oh, they'll initially argue and refuse to pay. As soon as thhe Sun starts dipping low, however, when the first howls start coming from the bars and the first drunken homeless zombie walks by reeking of ureene d'jour cologne, they'll be reaching for their wallet.
Another option to consider, since the police are already armed, is to simply authorize them to start robbing people at gunpoint. That's the entire mindset of the city council, anyway. "What's yours is ours."
More information about formatting options