Held:
1. Absent reasonable suspicion, police extension of a traffic stop
in order to conduct a dog sniff violates the Constitution’s shield
against unreasonable seizures.
A routine traffic stop is more like a brief stop under Terry v. Ohio,
392 U. S. 1, than an arrest, see, e.g., Arizona v. Johnson, 555 U. S.
323, 330. Its tolerable duration is determined by the seizure’s “mission,”
which is to address the traffic violation that warranted the
stop, Illinois v. Caballes, 543 U. S. 405, 407 and attend to related
safety concerns. Authority for the seizure ends when tasks tied to
the traffic infraction are—or reasonably should have been—
completed. The Fourth Amendment may tolerate certain unrelated
investigations that do not lengthen the roadside detention, Johnson,
555 U. S., at 327–328 (questioning); Caballes, 543 U. S., at 406, 408
(dog sniff),
but a traffic stop “become unlawful if it is prolonged beyond
the time reasonably required to complete th[e] mission” of issuing
a warning ticket, id., at 407.
Beyond determining whether to issue a traffic ticket, an officer’s
mission during a traffic stop typically includes checking the driver’s
license, determining whether there are outstanding warrants against
the driver, and inspecting the automobile’s registration and proof of
insurance. These checks serve the same objective as enforcement of
the traffic code: ensuring that vehicles on the road are operated safely
and responsibly. See Delaware v. Prouse, 440 U. S. 648, 658–659.
Lacking the same close connection to roadway safety as the ordinary
inquiries, a dog sniff is not fairly characterized as part of the officer’s
traffic mission.
In concluding that the de minimis intrusion here could be offset by
the Government’s interest in stopping the flow of illegal drugs, the
Eighth Circuit relied on Pennsylvania v. Mimms, 434 U. S. 106. The
Court reasoned in Mimms that the government’s “legitimate and
weighty” interest in officer safety outweighed the “de minimis” additional
intrusion of requiring a driver, lawfully stopped, to exit a vehicle,
id., at 110–111. The officer-safety interest recognized in Mimms,
however, stemmed from the danger to the officer associated with the
traffic stop itself. On-scene investigation into other crimes, in contrast,
detours from the officer’s traffic-control mission and therefore
gains no support from Mimms.
The Government’s argument that an officer who completes all traffic-related
tasks expeditiously should earn extra time to pursue an
unrelated criminal investigation is unpersuasive, for a traffic stop
“prolonged beyond” the time in fact needed for the officer to complete
his traffic-based inquiries is “unlawful,” Caballes, 543 U. S., at 407.
The critical question is not whether the dog sniff occurs before or after
the officer issues a ticket, but whether conducting the sniff adds
http://www.supremecourt.gov/opinions/14pdf/13-9972_p8k0.pdf