According to the Chicago Tribune, on May 7, 2009, a three-judge panel of Wisconsin Court of Appeals unanimously ruled that police "can attach GPS to cars to secretly track anybody’s movements without obtaining search warrants" without violating the Fourth Amendment. The court’s opinion in State v. Sveum can be found here. The defendant Sveum was under investigation for stalking when the police obtained a warrant to secretly place a GPS device on his car while it was parked in the his driveway. The device recorded the defendant’s movements for five weeks, after which time police retrieved it and used the information on it to obtain a warrant to search the defendant’s residence.
More recently, on May 12, the New York Court of Appeals (that state’s highest court), ruled that placing a GPS tracking device inside the bumper of a suspect’s car without a warrant, and using that device to monitor the suspect’s movements for two months, violated the suspect’s rights under the New York State Constitution. The court’s opinion in People v. Weaver can be found here.
The Wisconsin court first found that placing the device on Sveum’s car in his driveway did not violate the Fourth Amendment because the driveway was a public place. In rejecting the defendant’s argument that the device followed him into areas out of the public view (such as his garage), the court held that the device only gave the police as much information as visual surveillance would have. As noted by the Wisconsin Law Journal, the court followed a decision from the United States Court of Appeals for the Seventh Circuit and concluded that "no privacy interest protected by the Fourth Amendment  is invaded when police attach a device to the outside of a vehicle, as long as the information obtained is the same as could be gained by the use of other techniques that do not require a warrant." Nevertheless, the court was "more than a little troubled . . . [that] police are seemingly free to secretly track anyone’s public movements with a GPS device."
The New York court was even more concerned. It ruled that under the New York State Constitution, the New York defendant had a reasonable expectation of privacy that was infringed by the placement of the GPS device on his car and the use of that device to monitor his movements for two months. As such, there had been a search under the New York Constitution, and that the search was illegal because it was conducted without a warrant (or justification to excuse the lack of a warrant).
The use of GPS devices to monitor suspect’s movements is bound to become a hot-button issue over the next few years. Both the New York and Wisconsin courts expressed great concern about the threat to privacy posed by the rapid progression in monitoring technology. Moreover, the last Supreme Court decision to substantively address a similar issue was over 25 years ago, in, U.S. v. Knotts, 460 U.S. 276 (1983). In Knotts, the Court upheld the surreptitious installation of a beeper tracking device (a radio transmitter emitting periodic signals to enable tracking in a container of chloroform). This was because "a person traveling in automobiles on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another." The New York state court in Weaver noted that the amount of information that could be gathered from by a GPS device is much greater than a beeper in 1983 and so court may reach different results in teh future based on the technology at issue.
- May 7, 2009 Chicago Tribune article by Ryan J. Foley: "Wisconsin court upholds GPS tracking by police";
- The Wisconsin court’s opinion in State v. Sveum;
- May 12, 2009 Wisconsin Law Journal article by David Ziemer: "Fourth Amendment is not implicated by tracking"
- New York Court of Appeals’ opinion in People v. Weaver.