Technology is changing the way private investigators work. Thanks to smartphones and poweful databases, investigators no longer need to lug around heavy equipment or rifle through directories. However, new techologies present new legal challenges - and nothing signifies that more than the spread of GPS tracking devices. 

This level of convenience and power of GPS trackers has proven tempting for all sorts of purposes. Car dealers have used them to track down and repossess cars, spouses have used them to track their significant others, police have used them to trail suspects, and parents have used them to keep their kids safe. Private investigators have gotten in on the action for all sorts of surveillance cases too - after all, why hang out in a car all night when you can stick a small device on a vehicle and track it for months on end?

However, the law has failed to keep up with technologies' rapidly expanding abilities. Before you go out and plant a GPS tracking device on someone's vehicle (or ask a private investigator to do it for you), you should understand when it’s OK, when the law is unclear, and when it’s most definitely illegal.

Case by Case: When is it OK to use a GPS Tracking Device?

The law is still unclear on the use of GPS trackers - in fact, cases involving them have gone all the way to the supreme court. Between the 4th amendment's restrictions on unreasonable search and seizure, various court rulings, and state laws, one thing is clear: putting a GPS tracking device on a car will place you on shaky legal territory. Before we get into how courts have ruled on using GPS trackers in the past, beware -the law is unsettled and subject to change. Oh, and none of this is legal advice, or a substitute for legal advice - seek counsel before doing anything.

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Do You Own the Car? It’s Probably Legal

Generally speaking, if you own the vehicle you are seeking to track, the law has sided with you so far. For example, Coca Cola was sued by an employee after it used GPS tracking on a company issued car. The court ruled in favor of Coca Cola, and other courts have ruled similarly in comparable cases.


Do You Part-Own the Car? Then the Law is Unclear.

If you jointly own the car, it’s another matter. A number of courts have ruled that it is OK to track cars that are jointly owned, so long as one of the owners consents to the tracking. In Minnesota in 2011, a court ruled that it was OK for a private investigator or 3rd party to place a tracking device on a car, so long as one of the owners consented - effectively making it OK for one spouse to track another spouse.

However, the law is far from clear on this matter, and is subject to change. Some states have specific laws relating to GPS tracking and consent (see below). Even if you don’t end up criminally liable for tracking a jointly owned car, you could still open yourself up to a civil suit, and using any evidence gathered by the device in divorce proceedings may not look good in court.

Finally, there are cyberstalking laws that deal with this too - athough they have also failed to address part ownership. Certianly, the ethics can be difficult to deal with as well. Aside from the issue of whether permission from one party is sufficient, investigators should always be sure that the client does not wish harm on the person of interest (POI), as they should in every case whether it involves GPS surveillance or not.


Don’t Own the Car? It’s Not Legal

If it’s not your car, you’re out of luck. The New York Department of Labor used a GPS device on an employee’s personal car, and the employee sued. After initially siding with the employer, on appeal the courts ruled that it was an unreasonable search. They did so in part because the employer tracked a personal car 24/7 for a month, which they considered an invasion of privacy and not necessary for the purposes of the Department's investigation into the employee.

There are also a number of states that have specific laws about this that go beyond 4th amendment protections (see below). Even if you track a car in a state not covered by one of these laws, there are potential civil suits for invasion of privacy, and even criminal liability for stalking. 


Does Your Business Own the Car? It’s Most Likely OK.

If your business owns the car, the law seems to have sided with you so far. In a variety of cases concerning employees suing employers for using GPS tracking devices on their work-issued cars, the courts have ruled with the employers. 


Investigating an Employee? It Depends.

Things get a little murkier if you’re looking to track a personal vehicle being used for work purposes. Personally owned taxis have been deemed fair game in the past, while personal cars used outside of work have been considered off limits. In these cases, it seems that the best bet is to limit the scope of tracking to a specific time period, for a specific purpose, and in a public setting. Whether the person being tracked has "a reasonable expectation of privacy" is one of the main factors at play here - but whatever the case, you're definitely on shaky legal ground.

If consent is given to track the car, most issues with legality seem to go away. Indeed, some states have laws that specifically allow for tracking cars when permission is given.


Tracking Your Child? It’s Probably OK.

Tracking a minor (under 18, of course) in your care has rarely been challenged, and is specifically exempted in some state's laws. It goes without saying that tracking someone else’s child without permission is most definitely not OK on ethical grounds, never mind legal grounds.


Protecting Assets or Collateral? It Depends.

"Buy Here Pay Here" dealers selling vehicles to people with bad credit often use GPS tracking devices to lower their financial exposure if buyers default on payments. Generally speaking this is OK, so long as the buyer is informed of the tracker. In 2011, Florida’s Attorney General sued a car dealer for installing GPS tracking devices without permission.

Are You a Member of Law Enforcement? It's Illegal Without a Warrant.

Generally, a warrant is required. Several cases involving GPS trackers installed by police have resulted in the evidence collected by the device being thrown out for violating the defendant’s 4th amendment rights. In 2012, a landmark case between the District of Columbia and Antoine Jones ruled that without a correctly executed and adhered to warrant, evidence collected by GPS tracking devices installed on a vehicle was unconstitutional.



State-Specific Laws

Federal law might be a bit behind the times, but some states have chosen to pass specific laws about when you can and cannot use a GPS tracker on someone’s vehicle. As far as we know, none of these laws have clarified whether consent from one or both owners is sufficient if vehicle is jointly owned.

These states specifically require notice and/or consent:

These states specifically allow the use of GPS trackers when consent is given:

How Tracking Devices Work

GPS trackers themselves are relatively simple devices. Often as small as a packet of cigarettes, the covert types can be affixed to a vehicle using tape, Velcro, or magnets, and run on battery power (sometimes for up to 6 months). Other types can be installed under the hood or near the dashboard and are powered by the car’s own battery - effectively allowing them to track the vehicle indefinitely. Once installed, you usually track them from a website or an app, often for a monthly fee.

Fixing them to a vehicle can present some problems. Even if you have permission (or a warrant) to install it, you still need to avoid trespassing on private property when installing it. Trespassing is a serious crime which could void any evidence later collected by the device.

Alternatives to GPS Tracking Devices

GPS tracking is not the only way to know where someone is. There are a number of old school (and new school) ways to see where someone's going what they’re doing - often with far more detail than a GPS tracker could ever tell you.

  • Surveillance and stakeouts. GPS trackers can, by nature, only see where a vehicle is.  A private investigator can follow a person so long as they are on public property, which means they can report who they meet with and what they do. They can also collect evidence of any activities in a way that’s admissible in court, and free of the legal troubles that surround the use of GPS trackers.
  • Number plate spotting  and tracking databases. Not many people know that databases of vehicle sightings and movements exist, and are available to law enforcement and licensed private investigators. These databases use cameras mounted on vehicles like police cars and tow trucks to automatically snap photos of any number plates they see. The result is a searchable database that can show you all the recent sightings of a vehicle on a map, sometimes up to  6 months in the past. This can help private investigators conduct surveillance more efficiently, or place a person in a a certain location at a certain time.


The world of GPS trackers is as legally complicated as it is technically simple. Trackers are easy to use, but difficult to deploy legally and ethically. Private investigators always make sure that their clients are not seeking to harm who they track, but sellers of GPS tracking equipment are not always so discerning. If you are going to use a tracker, be  aware of the legal questions that surround them, and consult legal counsel beforehand. At some point, the law will catch up to technology - and you don’t want to be on the wrong side of it when it does.


Danny Boice
Danny Boice

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