Cops and Cars: How the Automobile Drove Fourth Amendment Law

56 Pages Posted: 21 Oct 2019 Last revised: 12 Dec 2019

See all articles by Tracey Maclin

Tracey Maclin

University of Florida Levin College of Law

Date Written: 2019


This is an essay on Professor Sarah A. Seo’s new book, Policing the Open Road: How Cars Transformed American Freedom (Harvard Univ. Press 2019). I focus on Professor Seo’s analysis of Carroll v. United States, 267 U.S. 132 (1925) and Brinegar v. United States, 338 U.S. 160 (1949). Carroll is important not only because it was the Court’s first car case. Understanding Carroll (and Brinegar, which solidified and expanded Carroll’s holding) is essential because, nearly one hundred years later, its logic continues to direct how the modern Court resolves Fourth Amendment claims of motorists. Put simply, a majority of today’s Justices view the Fourth Amendment rights of motorists essentially the same way that a majority of the Justices did in 1925. Specifically, Part I highlights Seo’s major assertions regarding Carroll; Carroll’s influence on another controversial search and seizure decision, Terry v. Ohio, 392 U.S. 1 (1968), which upheld an officer’s power to stop and frisk a person he suspects is armed and dangerous; and finally, Carroll’s connection to the police authority upheld by the Justices that permits the discretionary and discriminatory policing that currently pervades America’s highways and roads.

Part II of this essay focuses on the modern Court’s understanding of motorists’ privacy. Carroll’s vision of how the Fourth Amendment applies to searching cars was not inescapable. While many lawyers and law students today might not believe it, not so long ago several members of the Burger Court took the view that cars should be treated like other effects under the Fourth Amendment – which meant the warrant requirement would apply to cars. Though a majority of Justices never embraced the view that warrants are required to search the interior of vehicles, in a series of cases the Court went back and forth on whether warrants were needed to search private containers found in vehicles. Part II examines these cases and the Court’s flawed norm that motorists have diminished privacy interests in closed containers found in cars when police have probable cause to search. One could view these cases as adopting a narrower view of motorists’ privacy rights than the view embraced by Carroll. More importantly, the understanding that currently permits warrantless searches of suitcases and purses under the automobile exception, if meant to be a neutral principle, would also allow warrantless searches of computers and cell phones found in cars. I examine whether today’s Court will apply the automobile exception to searches of computers, cell phones and other electronic devices found in vehicles.

Keywords: criminal procedure, search and seizure, fourth amendment, police, cars, automobile exception, privacy, warrants, searches of computers, cell phones and electronic devices

Suggested Citation

Maclin, Tracey, Cops and Cars: How the Automobile Drove Fourth Amendment Law (2019). Forthcoming, Boston University Law Review, Vol. 99, No. 5, 2019, Boston Univ. School of Law, Public Law Research Paper No. 19-28 , Available at SSRN:

Tracey Maclin (Contact Author)

University of Florida Levin College of Law ( email )

P.O. Box 117625
Gainesville, FL 32611-7625
United States

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