Which statement summarizes Knowles v. Iowa?

• A. It permits searches incident to routine traffic stops.
• B. It bans all searches during traffic stops.
• C. It authorizes warrantless searches in traffic stops.
• D. It prohibits searches incident to the issuance of a routine citation.

Answer: (D)

Knowles v. Iowa sets a clear limit on what a police officer can do during a routine traffic stop. The Fourth Amendment protects against unreasonable searches, and the search-incident-to-arrest rule applies only when there is a custodial arrest. In this case, the stop ends with a ticket and no arrest, so a search of the vehicle cannot be justified as a search incident to arrest. This means the act prohibits performing such a search merely because a routine citation was issued.

If there is another valid basis to search—like probable cause to search the vehicle, consent to search, or another recognized exception—those can still apply, but a routine citation alone does not authorize a vehicle search.