Unpaid parking tickets are a common problem for cities. In July 2009, the city of Portsmouth, Maine had $750,000 in unpaid parking tickets. Why do people avoid paying parking tickets even though many of them are less than $20? In most cities, there is no immediate penalty for not paying a parking ticket. But if the tickets go unpaid and there are many of them, some agencies will take out a warrant for your arrest and you will have to sit in jail until you pay the fine. Some cities are beginning to use a wheel interlocking device called the "boot" that immobilizes your vehicle. Atlanta officials agreed to use the boot on people who had unpaid parking tickets in July 2009. Officers are allowed to run tag numbers and anyone who comes up with unpaid parking tickets could get the boot - even if they are parked legally at the time.