Also known as: traffic stops · traffic-stop · vehicle stop · motor vehicle stop
Written by attorneys · grounded in primary & secondary sources — see below
A temporary detention of a motor vehicle and its occupants by law enforcement officers based on probable cause or reasonable suspicion of a traffic violation. The encounter is limited in scope and duration to the purpose of the stop unless additional justification arises. Officers may take certain safety measures and conduct limited investigations during the detention without converting it into an unlawful seizure.
Theo Thomas was driving when an officer stopped the car for a broken taillight. The officer noticed a bulge under the passenger's jacket and developed reasonable suspicion that the passenger was armed. The officer conducted a patdown of the passenger during the stop.
Timothy Tang was pulled over for speeding. While the officer processed the citation, a trained narcotics dog alerted on the vehicle. The alert supplied probable cause for a search of the car.
Taliah Tang was stopped for an equipment violation. An officer walked a drug-detection dog around the car while another officer handled the license check. The sniff occurred without extending the stop beyond the time needed for the traffic matter.
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Tracy Torres rode as a passenger when officers stopped the vehicle for a traffic infraction. The officers directed Tracy to exit the car for safety reasons even though they had no individualized suspicion that Tracy posed a danger.
Travis Tate was stopped after an officer observed a missing license plate light. The officer later admitted the stop was also meant to investigate an unrelated tip. The stop remained valid because the equipment violation supplied an objective basis.
Thomas Thompson was stopped for speeding at night in a rural area. The driver appeared nervous and the officer saw a knife on the floorboard. The officer searched the passenger compartment for weapons before allowing the occupants to reenter the car.
A traffic stop is reasonable under the Fourth Amendment when officers have probable cause to believe a traffic violation has occurred. The stop remains valid regardless of any additional investigative motive.
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Officers may order passengers out of a lawfully stopped vehicle for officer safety even without individualized suspicion that the passengers are dangerous.
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A dog sniff of a vehicle's exterior during a lawful traffic stop is not a search if it does not prolong the stop beyond the time needed to handle the traffic violation. No separate reasonable suspicion of drug activity is required.
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Officers may frisk a passenger if they have reasonable suspicion that the passenger is armed and dangerous. The suspicion need not relate to criminal activity beyond the stop itself.
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A trained and certified narcotics dog's alert during a traffic stop can provide probable cause to search the vehicle absent special circumstances undermining the dog's reliability.
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…existence only because of the tip. Again, our decision rested in part on our view of the danger presented to police officers in "traffic stop" and automobile situations.[^maj-13] Finally, we have also expressly recognized that suspects may injure police officers and others by virtue of their access to weapons, even though they…