The laws governing GPS tracking by government agents, police or private citizens are not definitive. The Fourth Amendment and other state and federal laws grant United States residents certain protections to their privacy, including strict limits on illegal search and seizure. But there's nothing in the Constitution that specifically addresses GPS tracking technology — or many other forms of electronic surveillance.
The Supreme Court and several lower courts have issued rulings on GPS in 2012, but those decisions addressed narrow uses of the technology by police and employers, respectively. The courts didn't address the use of GPS tracking devices by private citizens.
Before you use a GPS tracking device on a vehicle you don't own, you should do a little research on current federal and state laws.
As of now, here's what private citizens need to know about GPS tracking and the law:
It's generally legal to use a GPS tracking device if:
You or your company own the vehicle
You or your company do not own the vehicle, but you place the GPS device on the outside of the car — under the rear bumper, for example
The vehicle is visible to the public — in a parking lot or a public street, for example
You could obtain the same information by physically trailing the vehicle
The vehicle is not situated on someone else's private property
It's generally illegal to use a GPS tracking device if:
You need to break into the vehicle to situate the device
You need to physically hardwire the device inside the vehicle
The vehicle is in a place where its owner has a reasonable expectation of privacy — in a private garage, for example
With its recent ruling on GPS tracking by police, the Supreme Court left many questions unanswered. But the justices signaled that they were ready to delve more deeply into electronic surveillance issues.