Code of Criminal Procedure · U.S. Supreme Court, 1925

Carroll v. United States

Carroll v. United States is a 1925 U.S. Supreme Court decision. This page summarizes key points and works through practice questions for Texas peace officer exam preparation.

Key points

  • Vehicle readily mobile
  • Probable cause that the vehicle contains contraband or evidence subject to seizure
  • No separate warrant required
  • Scope (from later cases Ross and Acevedo): any part of the vehicle and any container that could hold the object of the search

Learn more about this topic

Time yourself, score your run, review missed questions with statute references — Free Practice Pass cadets get limited access.

Start Free Practice

Worked examples

Worked example 1

Under the automobile exception, officers may search a vehicle without a warrant when:

  1. The vehicle is parked
  2. They have probable cause to believe the vehicle contains contraband or evidence of a crime Correct
  3. The driver is over 21
  4. Anytime during a traffic stop
Why: The automobile exception allows a warrantless search of a readily mobile vehicle when there is probable cause that it contains contraband or evidence (Carroll). Later cases set the scope: any part of the vehicle and any container that could hold the object of the search (United States v. Ross; California v. Acevedo).
Statute: Carroll v. United States; Chambers v. Maroney; California v. Acevedo
Worked example 2

SCENARIO. An officer smells a strong odor of fresh marijuana coming from the open driver's window of a stopped vehicle. Under Texas law, the smell of marijuana:

  1. Is not a basis for any further investigation
  2. Standing alone, has historically supplied probable cause to search the vehicle (post-2019 hemp law has prompted some prosecutors to require additional corroboration but the general rule remains intact in most jurisdictions) Correct
  3. Authorizes a full custodial arrest of all occupants
  4. Justifies a full search of the home
Why: Texas appellate courts have long held that the odor of marijuana from a vehicle supplies probable cause to search under the automobile exception. After the 2019 hemp legalization, prosecutors and policy guidance often urge officers to articulate additional facts (e.g., visible plant material, admissions, paraphernalia) but the legal sufficiency of odor-PC for vehicle searches generally remains intact.
Statute: Texas case law (probable cause via odor); Carroll v. United States