Your vehicle’s automatic vehicle location (AVL) is automatically collected by your car’s computer-aided dispatch (CAD) system. Most modern vehicles have a CAD system that tracks the vehicle’s location either via cellphone tower locations or through global positioning system (GPS) data. For the most part, you probably never even think about your AVL data or CAD system — unless maybe you have a service like OnStar that will track your location and send out messages on your behalf if you’re in an accident.

AVL data can also be helpful, however, in criminal traffic cases involving excessive speeding. Much of the time, officers make the call on how fast a driver is going by following that driver and matching pace with them for a few moments. They judge the other driver’s speed by their own vehicle’s pace.

But “pacing” is a very imprecise tool — and human beings also make mistakes. When there’s some question about what actually happened and whether an officer really identified the right driver or clocked the right speed, the AVL data from both vehicles can be compared. If they don’t match up — meaning that an officer wasn’t really going as fast as they thought or wasn’t in the location that they claimed — it can show a mistake of fact that could help your case.

If you’re absolutely sure that the arresting officer couldn’t possibly have clocked you going as fast as they claimed, it may be worthwhile to look into the AVL data that pertains to the incident. An experienced criminal traffic attorney can discuss your options for this kind of defense.