The City of Harrisonburg, Va, has replaced tire chalking with a high tech system by Craig Bagdon’s Park Trak. The hand held unit enables parking officers to record license plates using a built in LPI system. They can then return a set time later and the system determines whether or not the car has overstayed its "welcome."
Another neat feature is the ability to enter the location of the vehicle’s valve stem to determine whether or not the car has simply been moved to the next space.
The hand held contains a record of tickets past and if a vehicle is owned by a scofflaw, it can notify the patrol who can have the vehicle towed.