[ Rehnquist ]
The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader.
See United States v. Detroit Timber & Lumber Co., 200 U.S. 321, 337.
KNOWLES v. IOWA
CERTIORARI TO THE SUPREME COURT OF IOWA
An Iowa policeman stopped petitioner Knowles for speeding and issued him a citation rather than arresting him. The officer then conducted a full search of the car, without either Knowles consent or probable cause, found marijuana and a pot pipe, and arrested Knowles. Before his trial on state drug charges, Knowles moved to suppress the evidence, arguing that because he had not been arrested, the search could not be sustained under the search incident to arrest exception recognized in United States v. Robinson, 414 U.S. 218. The trial court denied the motion and found Knowles guilty, based on state law giving officers authority to conduct a full-blown search of an automobile and driver where they issue a citation instead of making a custodial arrest. In affirming, the State Supreme Court applied its bright-line search incident to citation exception to the Fourth Amendments warrant requirement, reasoning that so long as the officer had probable cause to make a custodial arrest, there need not in fact have been an arrest.
Held: The search at issue, authorized as it was by state law, nonetheless violates the Fourth Amendment. Neither of the two historical exceptions for the search incident to arrest exception, see Robinson, supra, at 234, is sufficient to justify the search in the present case. First, the threat to officer safety from issuing a traffic citation is a good deal less than in the case of a custodial arrest. While concern for safety during a routine traffic stop may justify the minimal additional intrusion of ordering a driver and passengers out of the car, it does not by itself justify the often considerably greater intrusion attending a full field-type search. Even without the search authority Iowa urges, officers have other, independent bases to search for weapons and protect themselves from danger. Second, the need to discover and preserve evidence does not exist in a traffic stop, for once Knowles was stopped for speeding and issued a citation, all evidence necessary to prosecute that offense had been obtained. Iowas argument that a search incident to citation is justified because a suspect may try to hide evidence of his identity or of other crimes is unpersuasive. An officer may arrest a driver if he is not satisfied with the identification furnished, and the possibility that an officer would stumble onto evidence of an unrelated offense seems remote. Pp. 36.
569 N. W. 2d 601, reversed and remanded.
Rehnquist, C. J., delivered the opinion for a unanimous Court.