Sunday, October 08, 2006

GPS Tracking and the 4th Amendment: Part 1

As you may know, police often use GPS devices to monitor the movements of vehicles used by those who are suspected of being involved in criminal activity. The use of these devices is becoming increasingly common because they are so effective.

The devices are usually attached somewhere on the exterior of the vehicle, under a bumper or on the undercarriage, say.

The use of GPS tracking devices is raising 4th Amendment issues, for several reasons. In this post I want to talk about what has been the most common issue: Whether the use of a tracking device is a "search" under the 4th Amendment.

To explain why this is an issue, I need to review what happened in a twenty year old Supreme Court case: In United States v. Knotts, 460 U.S. 276 (1983), the Supreme Court was asked to decide if law enforcement’s using a “beeper” to track the movements of a vehicle was a search under the 4th Amendment. If it was, law enforcement would have had to have gotten a search warrant for the use of the beeper to be constitutional; if it was not, then their using the beeper without getting a warrant did not violate the 4th Amendment.

The “beeper” was a radio transmitter that was placed in a container of chloroform that was sold to a suspect – Armstrong – who was believed to be involved in manufacturing illegal drugs. Armstrong put the container with the beeper in it in his vehicle and officers followed him to see where he was taking it. In following him, they relied both on visual surveillance and on the signals from the beeper; the beeper basically made it easier for them to keep track of Armstrong’s vehicle as he traveled along roads in rural Wisconsin. As its name implies, the beeper merely transmitted an audio signal that became stronger when the officers were closer to Armstrong’s vehicle and weakened as they fell further behind it.

The Supreme Court said the use of the beeper was not a “search” because Armstrong did not have a 4th Amendment expectation of privacy in his movements along public highways. The Knotts Court noted that the “fact that the officers . . . relied not only on visual surveillance, but also on the use of the beeper . . . does not alter the situation. Nothing in the Fourth Amendment prohibited the police from augmenting the sensory faculties bestowed upon them at birth with such enhancement as science and technology afforded them”.

Since Armstrong’s movements were not private, there was no search and the 4th Amendment was not implicated.
Given the Knotts decision, it would seem that law enforcement’s using GPS devices to track vehicles would not be a search within the 4th Amendment . . . which means law enforcement could install a GPS device on a vehicle and monitor it without obtaining a warrant, just as the officers did in Knotts. Some courts, though, are suggesting that Knotts is not dispositive of this issue because of the significant differences between GPS tracking devices and the beeper used in Knotts.

In State v. Jackson, 76 P.3d 217 (Wash. 2003), the Washington Supreme Court held that the use of a GPS tracking device is a search under the state’s constitution, which the court interprets as providing more privacy protection than does the 4th Amendment. The Jackson Court explained that the use of a GPS device is much more intrusive than the monitoring of the beeper used in Knotts:

“[W]hen a GPS device is attached to a vehicle, law enforcement officers do not in fact follow the vehicle. Thus, . . . the GPS device does not merely augment the officers' senses, but rather provides a technological substitute for traditional visual tracking. Further, the devices in this case were in place for approximately two and one-half weeks. It is unlikely that the sheriff's department could have successfully maintained uninterrupted 24-hour surveillance throughout this time by following Jackson. Even longer tracking periods might be undertaken, depending upon the circumstances of a case. We perceive a difference between the kind of uninterrupted, 24-hour a day surveillance possible through use of a GPS device, which does not depend upon whether an officer could in fact have maintained visual contact over the tracking period, and an officer's use of binoculars or a flashlight to augment his or her senses.

Other courts are suggesting that the same result may hold under the 4th Amendment, on the premise that the increased sophistication of GPS tracking makes it more intrusive than the use of the beeper at issue in Knotts and therefore should bring it within the scope of the 4th Amendment.

A New York court concluded, for example, that “[a]t this time, more than ever, individuals must be given the constitutional protections necessary to their continued unfettered freedom from a `big brother’ society. . . . [A] person must feel secure that his or her every movement will not be tracked except upon a warrant based on probable cause establishing that such person has been or is about to commit a crime. Technology cannot abrogate our constitutional protections.” People v. Lacey, 787 N.Y.S.2d 680 (N.Y. Co. Ct. 2004).

A federal district court in Maryland noted that the use of GPS technology raises issues that may implicate the 4th Amendment, but concluded it did not have to decide whether this is true because the officers in the case had obtained a warrant before they installed the GPS device on the suspect’s vehicle. United States v. Berry, 300 F.Supp.2d 366 (D. Md. 2004).

It’s likely to be a long time before the Supreme Court addresses this issue if, indeed, it ever does. This means the applicability of the 4th Amendment to GPS tracking will probably remain uncertain, dependant upon whether a court construes GPS technology as indistinguishable from the beeper used in Knotts or as a device the intrusiveness of which takes it out of the Knotts holding. We may also see state courts using state constitutions to impose restrictions on the use of this technology.

The question as to whether GPS tracking constitutes a search within the compass of the 4th Amendment is really just one manifestation of a larger issue: How do we apply constitutional protections -- such as the 4th Amendment -- to evolving technologies? The constitution, and the 4th amendment in particular, were written at a time when the only world was the real, physical world and searches involved law enforcement's kicking down doors and rummaging through closets and other "private" areas.

Technology lets law enforcement officers do what they could not do when the Constitution was drafted. Here, as in other areas, courts need to decide how we reconcile new technologies, new methods, with traditional principles.


Joshua Engel said...

I find the thoughts here very provocative.

Relying on Supreme Court cases from the early 1980’s, law enforcement has not sought a warrant before using GPS devices without a warrant. These precedents established that the use of electronic tracking devices on vehicles did not constitute a search – and, accordingly, did not implicate the Fourth Amendment – because people do not have a reasonable privacy interest in the movement of their vehicles when traveling on a public roadway. Until recently, Federal courts have, on the basis on these decisions, almost universally upheld the use of GPS tracking devices. I agree, however, with the recent decision by the D.C. Circuit Court recognizing that people have a reasonable expectation of privacy in the totality of their movements over the course of a period of time.

I have written on this at I have also posted an article I am publishing this winter on the subject here:

Susan Brenner said...

Thanks for the comment, Joshua.

You might check out a couple of recent posts I've done on the GPS issues, too.