The New Jersey appellate court addressed the legality of using GPS trackers in marital infidelity cases. The Court held that the use of such technology was not an invasion of privacy, given that the tracker is merely reporting what any member of the public could see--the position of the vehicle.
This issue comes up frequently in family law, as it is a common tool used by private investigators and sometimes the spouses themselves. The GPS tracker is placed on the car, and transmits the locations of the vehicle in intermittent bursts. Typically this information in and of itself is not used as evidence, but it is used to determine where the spouse may be meeting his/her paramour. Before engaging in such plan, it is advisable to consult with an attorney to ensure any evidence gained will be legally admissible.