As technology continues to advance, what was once thought novel, even a luxury, quickly becomes commonplace, even a necessity. Global Positioning System (GPS) technology is one such example. Generally, GPS is a satellite-based technology that discloses the location of a given object. This technology is used in automobiles and cell phones to provide individual drivers with directional assistance. Just as individuals are finding increasing applications for GPS technology, state and federal governments are as well. State and federal law enforcement use various forms of GPS technology to obtain evidence in criminal investigations. For example, federal prosecutors have used information from cellular phone service providers that allows real-time tracking of the locations of customers’ cellular phones. Title III of the Omnibus Crime Control and Safe Streets Act of 1958 (P.L. 90-351) regulates the interception of wire, oral, and electronic communications. As such, it does not regulate the use of GPS technology affixed to vehicles and is beyond the scope of this report.

The increased reliance on GPS technology raises important societal and legal considerations. Some contend that law enforcement’s use of such technology to track motor vehicles’ movements provides for a safer society. Conversely, others have voiced concerns that GPS technology could be used to reveal information inherently private. Defendants on both the state and federal levels are raising Fourth Amendment constitutional challenges, asking the courts to require law enforcement to first obtain a warrant before using GPS technology.

Subject to a few exceptions, the Fourth Amendment of the U.S. Constitution requires law enforcement to obtain a warrant before conducting a search or making a seizure. Courts continue to grapple with the specific issue of whether law enforcement’s use of GPS technology constitutes a search or seizure, as well as the broader question of how the Constitution should address advancing technology in general. The Supreme Court has not directly addressed the issue of whether law enforcement’s use of GPS technology in connection with motor vehicles falls within the Fourth Amendment’s purview. Lower federal courts have relied on Supreme Court precedent to arrive at arguably varying conclusions. For example, several district and circuit courts of appeals have concluded that law enforcement’s current use of GPS technology does not constitute a search, and is thus permissible, under the Constitution. To date, while the U.S. Supreme Court has not provided a definitive answer regarding law enforcement’s use of GPS technology, state legislatures and courts have approached the issue in various ways. Some states have enacted laws requiring law enforcement to obtain a warrant before using GPS technology. Some state courts have resolved the question under their own constitutions. Although they have reached somewhat differing conclusions, other state courts have relied on Supreme Court precedent, such as United States v. Knotts, 460 U.S. 276 (1983), to derive an answer.

This report discusses the basics of GPS technology, society’s reliance on it, and some of the related legal and privacy implications. In addition, the report examines legislative and judicial responses on both federal and state levels.