A buddy of mine that does PI work has a GPS cell phone in a black box hooked up with longer life battery the size of a pack of smokes. It only sends "pulses" when the car is in motion. Can be set from 1 minute to every 10. Battery can last 2 weeks but if tied into the car for power the battery is just a backup. Now if your car is stolen, forget calling the cops, YOU can track the car! YOU can surprise the idiot who stole it! Tracking is done via the internet, gives speed, time stamp along with latitude and longitude.