I've twice now been told in the course of casual conversation that recent changes to Missouri law grant police the right to detain and search the vehicles of drivers stopped for routine traffic violations, even if the driver refuses to grant permission to search, and without particular evidence that a crime has been committed. I decided to look into it.
Many examples of pertinent case law reject this rumor:
Missouri Court of Appeals Western District, State v. Maginnis (2004):
Maginnis contends that under the Fourth Amendment it is not reasonable for the officer, in a routine traffic stop, to detain travelers for the purpose of interrogation on matters unrelated to the traffic violation, without, at that point, having any reasonable, articulable grounds for suspicion of illegal activities. We agree.
Missouri Court of Appeals Eastern District, State v. Bradshaw (2003):
When the driver has produced a valid license and proof that he or she is entitled to operate the car, he or she must be allowed to proceed on his or her way, without being subject to further delay by police for additional questioning.
Missouri Court of Appeals Eastern District, State v. Watkins (2002):
[An] investigative detention may only last for the time necessary for the officer to conduct a reasonable investigation of the traffic violation. ... If a stop extends beyond the time reasonably necessary to effect its initial purpose, the seizure may lose its lawful character unless a new factual predicate for reasonable suspicion of another crime is found during the period of lawful seizure.
Missouri Court of Appeals Western District, State v. Woolfolk (1999):
The fact that the police may detain a person for a routine traffic stop does not justify indefinite detention, however. The detention may only last for the time necessary for the officer to conduct a reasonable investigation of the traffic violation.
Missouri Court of Appeals Western District, State v. Slavin (1997):
The period of lawful seizure for a traffic stop encompasses that time during which the officer may conduct a reasonable investigation of the traffic violation.
Note: Slavin appears to be the earliest explicit statement of this fact (and is referenced in each of the above opinions), but unfortunately pre-dates the earliest decision available in the online archives of the Missouri Court of Appeals. The above passage comes from State v. Watkins.
Relevant federal cases:
U.S. Supreme Court, Florida v. Royer (1983):
[A]n investigative detention must be temporary and last no longer than is necessary to effectuate the purpose of the stop.
...
The scope of the detention must be carefully tailored to its underlying justification.
Conclusion: this rumor has no basis in law.
