The leader of the Green Bay Police department proposed a law banning people from idling their unlocked cars in the city.
The city council took up the issue last night and decided to send it back to committee.
Police Chief Andrew Smith says people could get a ticket if they leave their keys in unlocked cars.
He says they saw an 11 percent increase in vehicle thefts last year.
Smith says every case costs taxpayers about $500.
He says officers will have to decide when to write a ticket.
Appleton also has a similar rule for idling vehicles.