Document ID: ./input/supremecourt_opinions/opinions/14pdf/13-9972_p8k0.pdf
Page Number: 8.0

Cite as:  575 U. S. ____ (2015) 

5 

Opinion of the Court 

II 
A seizure for a traffic violation justifies a police investi­
gation of that violation.  “[A] relatively brief encounter,” a 
routine traffic stop is “more analogous to a so-called ‘Terry 
stop’  . . .  than  to  a  formal  arrest.”    Knowles  v.  Iowa,  525 
U. S.  113,  117  (1998)  (quoting  Berkemer  v.  McCarty,  468 
U. S.  420,  439  (1984),  in  turn  citing  Terry  v.  Ohio,  392 
U. S.  1  (1968)).    See  also  Arizona  v.  Johnson,  555  U. S. 
323, 330 (2009).  Like a Terry stop, the tolerable duration 
of police inquiries in the traffic-stop context is determined
by the seizure’s “mission”—to address the traffic violation
that  warranted  the  stop,  Caballes,  543  U. S.,  at  407,  and 
attend  to  related  safety  concerns,  infra,  at  6–7.    See  also 
United States v. Sharpe, 470 U. S. 675, 685 (1985); Florida 
v.  Royer,  460  U. S.  491,  500  (1983)  (plurality  opinion) 
(“The  scope  of  the  detention  must  be  carefully  tailored  to
its  underlying  justification.”).    Because  addressing  the
infraction is the purpose of the stop, it may “last no longer 
than is necessary to effectuate th[at] purpose.”  Ibid.  See 
also Caballes, 543 U. S., at 407.  Authority for the seizure 
thus ends when tasks tied to the traffic infraction are—or 
reasonably  should  have  been—completed.  See  Sharpe, 
470 U. S., at 686 (in determining the reasonable duration
of a stop, “it [is] appropriate to examine whether the police
diligently pursued [the] investigation”).

Our  decisions  in  Caballes  and  Johnson  heed  these  con­

straints. 
In  both  cases,  we  concluded  that  the  Fourth 
Amendment  tolerated  certain  unrelated  investigations
that  did  not  lengthen  the  roadside  detention.    Johnson, 
555 U. S., at 327–328 (questioning); Caballes, 543 U. S., at 
406,  408  (dog  sniff).  In  Caballes,  however,  we  cautioned 
that a  traffic stop “can become unlawful if it  is prolonged 
beyond  the  time  reasonably  required  to  complete  th[e] 
mission”  of  issuing  a  warning  ticket.    543  U. S.,  at  407. 
And we repeated that admonition in Johnson:  The seizure 
remains  lawful  only  “so  long  as  [unrelated]  inquiries  do