                 Certiorari granted, June 24, 2013
             Vacated by Supreme Court, June 24, 2013




                        PUBLISHED


UNITED STATES COURT OF APPEALS
             FOR THE FOURTH CIRCUIT


UNITED STATES OF AMERICA,              
                Plaintiff-Appellee,
               v.                              No. 10-5008
MANTEL DELANCE MUBDI,
             Defendant-Appellant.
                                       
       Appeal from the United States District Court
 for the Western District of North Carolina, at Statesville.
          Richard L. Voorhees, District Judge.
               (5:08-cr-00051-RLV-DCK-1)

                 Argued: January 24, 2012

                 Decided: August 10, 2012

    Before SHEDD, DAVIS, and DIAZ, Circuit Judges.



Affirmed by published opinion. Judge Diaz wrote the opinion,
in which Judge Shedd joined. Judge Davis wrote a separate
opinion concurring in part and in the judgment.


                         COUNSEL

ARGUED: Matthew Segal, Assistant Federal Defender,
FEDERAL DEFENDERS OF WESTERN NORTH CARO-
LINA, INC., Asheville, North Carolina, for Appellant. Amy
Elizabeth Ray, Assistant United States Attorney, OFFICE OF
2                  UNITED STATES v. MUBDI
THE UNITED STATES ATTORNEY, Asheville, North Car-
olina, for Appellee. ON BRIEF: Claire J. Rauscher, Execu-
tive Director, FEDERAL DEFENDERS OF WESTERN
NORTH CAROLINA, INC., Kevin A. Tate, Assistant Federal
Defender, Charlotte, North Carolina, for Appellant. Anne M.
Tompkins, United States Attorney, Melissa L. Rikard, Assis-
tant United States Attorney, OFFICE OF THE UNITED
STATES ATTORNEY, Charlotte, North Carolina, for Appel-
lee.


                         OPINION

DIAZ, Circuit Judge:

   Mantel Delance Mubdi entered a conditional guilty plea to
drug and firearms offenses, reserving the right to challenge
the district court’s denial of his motion to suppress evidence
seized during a traffic stop. The district court sentenced him
to 300 months’ imprisonment. On appeal, Mubdi contends
that the district court erred in denying his motion to suppress
because the officers who stopped his car did not have proba-
ble cause to execute the stop. As an alternative ground for
suppression, he contends that the officers unlawfully pro-
longed the traffic stop to conduct an open-air canine sniff of
his car. Mubdi also argues that the district court erred in
increasing his statutory mandatory minimum sentence for the
drug offenses based on improper judicial factfinding. Finding
no error, we affirm.

                              I.

                              A.

  On the morning of September 30, 2008, Mubdi was driving
a gray Dodge Magnum northbound on Interstate 77 near
Statesville, North Carolina. In the car with Mubdi was
                        UNITED STATES v. MUBDI                            3
Markus Parham. Two Statesville Police Department Officers,
Jason York and Phillip Wolfe, were parked in marked police
cruisers perpendicular to the highway about ten yards from
the right-hand side of the northbound lanes near exit 50.1 As
Mubdi approached the officers, they each visually determined
that he was driving above the posted speed limit of fifty-five
miles per hour.

   York observed a group of cars in front of Mubdi’s car trav-
eling the speed limit, and he noticed that Mubdi was closing
in on the group. He tracked Mubdi’s car for about a hundred
yards to estimate its speed at sixty-three or sixty-four miles
per hour. Wolfe likewise noticed Mubdi’s car gaining on the
cars in front of it and pulling away from the cars behind it; he
estimated Mubdi’s speed at sixty-five miles per hour. Because
of the angle at which the officers were parked, they were
unable to verify their estimates with radar equipment. How-
ever, York and Wolfe had both passed a radar certification
class that, among other things, provided training on how to
visually estimate the speed of vehicles within a narrow mar-
gin of error.

   The radar certification course constitutes a minimum of
thirty-two hours of training, which includes sixteen hours of
"supervised field practice where [officers] learn how to esti-
mate the speed of vehicles and how to operate the radar units
properly and to check off and set up the instrument and test
for accuracy." J.A. 106. Estimating speed is a mandatory part
of the certification process. Officers are trained to estimate
speeds both from a stationary position and while in motion.
An officer may err on any given estimate (or, indeed, all of
them) and still receive certification, provided that he errs in
the aggregate no more than forty-two miles per hour over
  1
   York, a nine-year veteran of the Statesville Police Department, is a
canine officer in the Department’s criminal interdiction unit. Wolfe, a ten-
year veteran of the Department, also works in the criminal interdiction
unit.
4                       UNITED STATES v. MUBDI
twelve separate speed estimates (an average margin of error
of three and a half miles).

   York and Wolfe pursued Mubdi for a few miles as he
merged from Interstate 77 onto Interstate 40 heading west.2
Wolfe passed Mubdi’s car in the left lane in an attempt to see
whether its occupants were wearing seatbelts. Mubdi then
merged behind Wolfe to pass a truck in the right lane. York,
trailing Wolfe and Mubdi, determined that Mubdi was follow-
ing Wolfe’s patrol car at a distance of no more than two to
three car lengths, contrary to the North Carolina Highway
Patrol’s recommendation that motorists keep at least a one car
length interval per ten miles per hour of speed.3

   At that point, York activated his blue lights to initiate a
traffic stop. After what struck York as "an extended amount
of time," id. 163, Mubdi pulled over to the side of the road.
York approached the car and asked for Mubdi’s driver’s
license and registration. He observed that Mubdi kept his foot
on the brake pedal, instead of shifting the transmission to park
and releasing the brake. Mubdi handed York a plastic pouch
containing his license and a vehicle rental contract. York saw
that Mubdi’s "hands were shaking more so than an average
person would be shaking for just a routine traffic stop" and
    2
     The district court viewed a video recording of the events as captured
by York’s dashboard camera.
   3
     The North Carolina statute proscribing motorists from following too
closely mandates that a "driver of a motor vehicle shall not follow another
vehicle more closely than is reasonable and prudent, having due regard for
the speed of such vehicles and the traffic upon and the condition of the
highway." N.C. Gen. Stat. § 20-152. Notably, the statute is silent as to
what constitutes a "reasonable and prudent" distance. York testified that
such a distance should be measured either by the Highway Patrol’s recom-
mendation or by the "two second rule" set out in the handbook of the Divi-
sion of Motor Vehicles for North Carolina drivers. The rule prescribes that
a driver "should allow two seconds between the time the vehicle ahead of
[the driver] passes a given point and the time [the driver’s] vehicle reaches
that same point." J.A. 160. According to York, Mubdi did not comply with
either standard.
                    UNITED STATES v. MUBDI                      5
that Mubdi looked scared. Id. 165-66. York asked Mubdi
whether he had rented the car, and Mubdi said that he had. In
response to York’s questions regarding the purpose of
Mubdi’s travel, Mubdi said he was headed to his grandfa-
ther’s funeral in Statesville and to his aunt’s house. Mubdi,
however, could not tell York his aunt’s name or where she
lived.

   York returned to his patrol car to review Mubdi’s license,
insurance, and rental contract, and to issue Mubdi a warning
ticket for speeding and following too closely. The rental con-
tract showed that the car had in fact been rented to Latonyia
Brathwaite, other drivers were explicitly forbidden from driv-
ing it, and the car was not permitted to travel outside of Geor-
gia. All told, it took York approximately fifteen minutes to
review Mubdi’s paperwork and to issue the warning ticket, a
time frame he described as typical. In the interim, Wolfe,
along with his drug-sniffing canine, arrived on the scene.

   After York completed the warning ticket for speeding and
following too closely, he approached Mubdi’s car to issue the
citation. He asked Mubdi to roll up the windows, turn off the
engine, and step out of the car. Mubdi complied but did not
shift the transmission into park. As a result, the car began roll-
ing away before Parham, still seated in the passenger seat,
stopped it. York explained the warning ticket and then told
Mubdi that Wolfe’s dog would conduct an open-air sniff
around the car.

   Captain Jacob Dyson, who arrived on the scene for backup,
approached the passenger’s side of the car, knocked on the
window, and asked Parham to get out. Parham just looked at
him, so Dyson tried the door handle. Parham then rolled down
his window, and, when Dyson again asked him to get out of
the car, Parham responded, "What for? I don’t have a gun."
Id. 113. When Parham started to reach between his legs to the
floorboard, Dyson feared that he was reaching for a firearm
and unsnapped his holster. Parham, however, got out of the
6                       UNITED STATES v. MUBDI
car without incident, and both he and Mubdi consented to a
pat-down for weapons. Shortly thereafter, Wolfe’s dog con-
ducted the open-air sniff and alerted. A search of the car
uncovered crack and powder cocaine, as well as two loaded
firearms, one under each front seat.

                                    B.

   A grand jury returned a superseding indictment charging
Mubdi with conspiracy to distribute and to possess with intent
to distribute a quantity of cocaine and at least fifty grams of
cocaine base, in violation of 21 U.S.C. § 846, possession with
intent to distribute a quantity of cocaine and at least fifty
grams of cocaine base, in violation of 21 U.S.C. § 841(a),
(b)(1)(A), (b)(1)(C), possession of firearms in furtherance of
drug trafficking crimes, in violation of 18 U.S.C. § 924(c),
and possession of firearms by a convicted felon, in violation
of 18 U.S.C. § 922(g)(1) and 18 U.S.C. § 924(e).

   Mubdi moved to suppress the drugs and firearms on the
grounds that the officers lacked probable cause to make a traf-
fic stop, lacked reasonable suspicion to prolong the stop to
conduct the canine open-air sniff, and conducted an illegal
warrantless search of the car.4 The district court denied
Mubdi’s motion. First, the court found that the officers had
probable cause to make the traffic stop because Mubdi was
speeding and following too closely. As to the first ground, the
court concluded that York and Wolfe were trained in visually
estimating vehicle speed and that their testimony regarding
Mubdi’s rate of speed was credible. After crediting the offi-
cers’ testimony and reviewing the video recording of Mubdi
changing lanes, the district court further found that the offi-
cers had probable cause to stop Mubdi for following too
closely.
    4
     Mubdi does not press this third ground on appeal.
                        UNITED STATES v. MUBDI                              7
   The court also determined that the duration of the stop was
reasonable, particularly given the objective facts that piqued
the officers’ growing suspicions. Finally, the court found that
the ensuing search of the car was proper on two independent
grounds: (1) Mubdi and Parham did not have a reasonable
expectation of privacy in the car in that neither of them was
an authorized driver on the rental contract, and (2) the officers
were justified in searching the car based on the canine alert
and Mubdi’s and Parham’s behavior.5

   Mubdi entered a conditional guilty plea to all charges,
reserving the right to appeal the denial of his suppression
motion. At the sentencing hearing, the district court adopted
the Presentence Investigation Report setting Mubdi’s offense
level at thirty and his criminal history category at IV. Mubdi’s
Guidelines sentence was 240 months on the drug charges, due
to the government’s filing of a notice of its intent to seek an
enhanced punishment under 21 U.S.C. § 851. The district
court imposed this sentence and a term of 120 months on the
possession of a firearm by a felon charge, to run concurrently.
Additionally, the district court imposed a mandatory consecu-
tive sixty-month sentence on the § 924(c) charge, yielding a
total term of 300 months’ incarceration. Mubdi timely
appealed.
  5
    Mubdi challenges both grounds on appeal. With respect to his pur-
ported privacy interest as a driver of the rental car, he argues that his case
is distinguishable from United States v. Wellons, 32 F.3d 117, 119 (4th
Cir. 1994), in which we held that an unauthorized driver of a rental car
lacks a reasonable expectation of privacy in the car, notwithstanding that
he may have the authorized driver’s permission. In Wellons, the evidence
sought to be suppressed was the fruit of an unlawful search. Id. Mubdi
contends, however, that the evidence he seeks to suppress is the fruit of
an unreasonably long seizure. Mubdi presses that, to the extent that Wel-
lons controls this case, we should revisit its holding and reach a contrary
conclusion. Because we agree with the district court that the canine alert
and Mubdi’s and Parham’s behavior alone justified the search, we need
not address this separate argument.
8                   UNITED STATES v. MUBDI
                               II.

   In considering the district court’s denial of a motion to sup-
press, we "review the district court’s legal determinations de
novo and its factual determinations for clear error." United
States v. Kelly, 592 F.3d 586, 589 (4th Cir. 2010). When the
district court has denied a suppression motion, we must "con-
strue the evidence in the light most favorable to the govern-
ment." Id. We are also to "particularly defer to a district
court’s credibility determinations, for it is the role of the dis-
trict court to observe witnesses and weigh their credibility
during a pre-trial motion to suppress." United States v. Abu
Ali, 528 F.3d 210, 232 (4th Cir. 2008) (quotation omitted).

                               A.

   Mubdi argues that the officers lacked probable cause to
believe he was speeding or following too closely. The rele-
vant law on this issue is well settled. Although a traffic stop
may be brief and for a limited purpose, it constitutes a "sei-
zure" under the Fourth Amendment and must "not be ‘unrea-
sonable’ under the circumstances." Whren v. United States,
517 U.S. 806, 809-10 (1996). Generally speaking, "the deci-
sion to stop an automobile is reasonable where the police have
probable cause to believe that a traffic violation has
occurred." Id. at 810; see also United States v. Branch, 537
F.3d 328, 335 (4th Cir. 2008) ("Observing a traffic violation
provides sufficient justification for a police officer to detain
the offending vehicle . . . ."). Probable cause exists if, given
the totality of the circumstances, the officer "had reasonably
trustworthy information . . . sufficient to warrant a prudent
[person] in believing that the petitioner had committed or was
committing an offense." Beck v. Ohio, 379 U.S. 89, 91 (1964).

                                1.

  Mubdi first argues that there was no probable cause to stop
him for speeding, notwithstanding that Officers York and
                    UNITED STATES v. MUBDI                     9
Wolfe independently estimated that he was driving eight to
ten miles above the posted speed limit.

   We have intimated, albeit in an unpublished opinion, that
an officer’s visual observation of a driver speeding may alone
be sufficient to establish probable cause. See United States v.
Daras, 164 F.3d 626, 1998 WL 726748, at *2 (4th Cir. 1998)
(per curiam) (unpublished table decision) ("[T]he Govern-
ment correctly points out that the officer’s visual estimate is
also sufficient, by itself, to support a conviction."); see also
United States v. Wornom, 754 F. Supp. 517, 519 (W.D. Va.
1991) (affirming a magistrate judge’s conviction of a defen-
dant for speeding based solely on an officer’s visual speed
estimate after radar evidence was suppressed).

   But we also recently concluded that "the Fourth Amend-
ment does not allow, and the case law does not support, blan-
ket approval for the proposition that an officer’s visual speed
estimate, in and of itself, will always suffice as a basis for
probable cause to initiate a traffic stop." United States v. Sow-
ards, No. 10-4133, slip op. at 14 (4th Cir. June 26, 2012). In
Sowards, this same district court denied a motion to suppress
evidence seized following a traffic stop of the defendant’s
vehicle, finding that the officer’s visual speed estimate (of
seventy-five miles per hour in a seventy mile per hour zone)
alone established probable cause to initiate the stop. Id. at 7-
8.

   We reversed, finding that it was clear error for the district
court to discount as immaterial the officer’s obvious difficulty
with measurements as it pertained to his ability to estimate the
defendant’s speed. Id. at 13. Among other patent errors, the
officer in that case testified that there are twelve feet in a
yard, twelve inches on a yardstick, and the number of inches
on a yardstick depends on the yardstick. Id. at 12. The officer
nonetheless insisted his estimate was accurate in that he had
tracked the vehicle for 100 yards. Because the record showed
that the officer was, to put it mildly, measurement-challenged,
10                    UNITED STATES v. MUBDI
we lacked confidence in his visual estimate, particularly given
the modest five mile per hour differential between the posted
speed limit and the defendant’s alleged speed. Id. at 19.

   The Sowards majority noted that our starting point in such
cases is to determine "whether a vehicle’s speed is estimated
to be in significant excess or slight excess of the legal speed
limit." Id. at 14. For significant excesses of the legal speed
limit, "the speed differential—i.e., the percentage difference
between the estimated speed and the legal speed limit—may
itself provide sufficient ‘indicia of reliability’ to support an
officer’s probable cause." Id. at 15 (emphasis added). On the
other hand,

      where an officer estimates that a vehicle is travelling
      in only slight excess of the legal speed limit, and
      particularly where the alleged violation is at a speed
      differential difficult for the naked eye to discern, an
      officer’s visual speed estimate requires additional
      indicia of reliability to support probable cause.

Id. at 16. While "[s]uch additional indicia of reliability," the
opinion expounded, "need not require great exactions of time
and mathematical skill that an officer may not have, . . . they
do require some factual circumstance that supports a reason-
able belief that a traffic violation has occurred." Id. at 18.

   Sowards further suggested that certain techniques, such as
"radar [or] pacing methods," id. at 17, might suffice to corrob-
orate an officer’s visual estimate in cases of slight excesses of
the legal speed limit. The majority opinion nevertheless
emphasizes, though, that the touchstone of the probable cause
inquiry is—as always—reasonableness, and the analysis
remains whether the "totality of the circumstances" estab-
lishes "the reasonableness of the officer’s visual speed esti-
mate." Id. at 17.6
  6
   Chief Judge Traxler wrote a vigorous and well-reasoned dissent in
Sowards, contending that the majority incorrectly imposed an iron-clad
                         UNITED STATES v. MUBDI                              11
   Here, even assuming that Mubdi was only slightly exceed-
ing the legal speed limit, the record supports the reasonable-
ness of the officers’ visual speed estimates, and thus the
decision to conduct the stop. Unlike in Sowards, we have
before us two independent and virtually identical estimates as
to Mubdi’s speed by officers who were required, as part of a
radar certification class, to visually estimate the speed of vehi-
cles within a narrow margin of error.7 In our view, this tan-
dem evidence alone provides sufficient corroboration to
support a finding of probable cause, particularly where the
record—again unlike the one in Sowards—does not cast a
shred of doubt on the officers’ ability to estimate speed or on
the accuracy of their visual estimates.

   In sum, we discern no clear error in the district court’s con-
clusion that Mubdi was speeding, based on its separate factual
findings that York and Wolfe were trained in estimating vehi-
cle speed and that their testimony regarding Mubdi’s rate of

rule prohibiting in every instance a probable cause finding based solely on
visual speed estimates where a vehicle is traveling only in "slight excess"
of the speed limit. Sowards, slip op. at 26 (Traxler, J., dissenting). In our
view, however, the majority’s opinion is not quite so inflexible, and it cer-
tainly does not purport to reject a district court’s consideration of the total-
ity of the circumstances in making its probable cause determination. Id. at
17. We are satisfied that the totality of the circumstances present here sup-
ports the district court’s ruling.
   7
     The fact that an officer may err on any given speed estimate and still
obtain certification, as discussed above, is not dispositive to our inquiry
here. The government’s probable cause burden requires no more than a
reasonable ground to believe that an offense has been committed, a stan-
dard far less exacting than that imposed on the government to prove guilt
beyond a reasonable doubt. Indeed, we recently emphasized that
"‘[f]inely-tuned standards such as proof beyond a reasonable doubt or by
a preponderance of the evidence, useful in formal trials, have no place in
a [probable cause] decision because probable cause is only the probability,
and not a prima facie showing, of criminal activity.’" United States v.
Ortiz, 669 F.3d 439, 445 (4th Cir. 2012) (quoting Illinois v. Gates, 462
U.S. 213, 235 (1983)).
12                  UNITED STATES v. MUBDI
speed was credible. Reviewing the probable cause determina-
tion de novo, we agree with the district court that the traffic
stop was supported by the officers’ reasonable belief that
Mubdi was speeding.

                               2.

   Mubdi also challenges the district court’s separate finding
that his following too closely behind Wolfe’s patrol car justi-
fied the traffic stop. Mubdi rightly notes that the North Caro-
lina statute proscribing motorists from following too closely,
N.C. Gen. Stat. § 20-152, is inapplicable when a motorist is
overtaking another. He contends that, because he was overtak-
ing a slower-moving truck in front of him in the right lane
when he merged behind Wolfe, his conduct was permissible.
As such, Mubdi argues that the officers made a mistake of law
by believing that he violated the statute. Tying up this argu-
ment, Mubdi asserts that the officers’ decision to stop him for
following too closely was improper because "a mistake of law
cannot provide reasonable suspicion or probable cause to jus-
tify a traffic stop." Appellant’s Reply Br. 4 (quoting United
States v. Chanthasouxat, 342 F.3d 1271, 1279 (11th Cir.
2003) (concluding that "an officer’s reasonable mistake of
fact may provide the objective grounds for reasonable suspi-
cion or probable cause required to justify a traffic stop, but an
officer’s mistake of law may not")).

   Mubdi’s argument here fails for two reasons. First, the evi-
dence is at best conflicting as to whether Mubdi merged in the
left lane behind Wolfe’s patrol car to overtake a slower-
moving vehicle, a necessary precondition for his conduct to
be permissible under the statute. On this point, Mubdi simply
averred that "there was a truck in front of [him] and to get
around it, [he] merged behind the officer that was on the
side." J.A. 269. On the other hand, York testified that "the
Dodge Magnum ma[d]e a left behind [Wolfe] in a very close
distance[, and] the truck [was] . . . at least ten car lengths in
front of [Mubdi]." Id. 162. Additionally, Wolfe stated that he
                     UNITED STATES v. MUBDI                     13
"wouldn’t say that [Mubdi] was getting ready to hit the truck
or anything. They had plenty of time—they had more time to
travel behind the vehicle before anything unsafe was to hap-
pen." Id. 250. In fact, the traffic stop video, submitted as an
exhibit to the motion, appears to bear out the officers’ testi-
mony.

   Viewing the evidence in the light most favorable to the
government, as we must when a motion to suppress has been
denied, Kelly, 592 F.3d at 589, Mubdi falls far short of show-
ing that his conduct was permissible under section 20-152 in
the first place.

   But even assuming that the officers were mistaken as to the
distance between Mubdi and the truck in front of him in the
right lane, and thus whether Mubdi merged into the left lane
to overtake the truck, such a mistake is patently a mistake of
fact. Nothing in the record suggests that the officers were
unaware that section 20-152 exempts drivers from the prohi-
bition on following too closely while they are overtaking a
slower-moving vehicle.

   Thus, to the extent that the officers honestly—although per-
haps mistakenly—believed that Mubdi was violating section
20-152 by following Wolfe too closely while not overtaking
a vehicle, this mistake is at most a reasonable one under the
circumstances, which does not undermine the district court’s
conclusion that the officers had probable cause to execute the
stop in the first instance. See Chanthasouxat, 342 F.3d at
1276 ("[I]f an officer makes a traffic stop based on a mistake
of fact, the only question is whether his mistake of fact was
reasonable.").

   Reviewing the probable cause determination de novo as it
pertains to Mubdi’s following too closely, we agree with the
district court that the traffic stop was justified on this basis as
well.
14                  UNITED STATES v. MUBDI
                              B.

   We next analyze whether the officers’ subsequent actions
were " ‘reasonably related in scope to the circumstances that
justified the [stop].’ " See United States v. Rusher, 966 F.2d
868, 875 (4th Cir. 1992) (quoting Terry v. Ohio, 392 U.S. 1,
20 (1968)). Traffic stops must be limited in both scope and
duration. See Florida v. Royer, 460 U.S. 491, 500 (1983) (plu-
rality opinion). With respect to scope, "the investigative meth-
ods employed should be the least intrusive means reasonably
available to verify or dispel the officer’s suspicion in a short
period of time." Id. As for duration, the police must "dili-
gently pursue[ ] a means of investigation that [is] likely to
confirm or dispel their suspicions quickly." United States v.
Sharpe, 470 U.S. 675, 686 (1985); see also Illinois v. Cabal-
les, 543 U.S. 405, 407 (2005) (noting that a traffic stop may
become "unlawful if it is prolonged beyond the time reason-
ably required to complete [its] mission"); Royer, 460 U.S. at
500 (noting that the scope of a seizure "must be carefully tai-
lored to its underlying justification," and that the government
bears the burden to "demonstrate that the seizure it seeks to
justify . . . was sufficiently limited in scope and duration to
satisfy the conditions of an investigative seizure").

   In the context of traffic stops, police diligence encompasses
requesting a driver’s license and vehicle registration, running
a computer check, and issuing a ticket. United States v. Fore-
man, 369 F.3d 776, 781 (4th Cir. 2004); see also Branch, 537
F.3d at 337 ("If a police officer observes a traffic violation,
he is justified in stopping the vehicle for long enough to issue
the driver a citation and determine that the driver is entitled
to operate his vehicle."). If a police officer seeks to prolong
a traffic stop to allow for investigation into a matter outside
the scope of the initial stop, he must possess reasonable suspi-
cion or receive the driver’s consent. Branch, 537 F.3d at 336.
Additionally, "if the driver obstructs the police officer’s
efforts in any way—for example, by providing inaccurate
                     UNITED STATES v. MUBDI                     15
information—a longer traffic stop would not be unreason-
able." Id.

  Addressing Mubdi’s argument that the officers unlawfully
prolonged the stop, the district court concluded as follows:

    The duration of the seizure was reasonable for the
    purpose of performing a routine traffic stop, particu-
    larly in light of the fact that it involved a determina-
    tion of a rental contract which was submitted by the
    driver, Mr. Mubdi. The time of the detention for the
    purpose of the traffic stop was reasonable under the
    circumstances and the totality thereof. And it was
    further testified [sic] by the growing reasonable sus-
    picion of the officers. So even taken as a gross
    amount of time, it’s still reasonable.

J.A. 338-39.

   On appeal, Mubdi asserts that the officers lacked reason-
able suspicion to detain him after York issued the warning
ticket, which resulted in the warrantless search of his car that
uncovered the drugs and firearms. We disagree.

   First, the district court correctly concluded that the officers’
actions were no more intrusive than necessary and that they
diligently pursued a means of investigation to confirm or dis-
pel their suspicions. In Branch, we held that a traffic violation
authorizes "a police officer to detain the offending vehicle for
as long as it takes to perform the traditional incidents of a rou-
tine traffic stop," such as "request[ing] a driver’s license and
vehicle registration, run[ning] a computer check, and issu[ing]
a citation." 537 F.3d at 335 (quotation omitted). The record
reveals that York did not stray from this holding, as he asked
Mubdi only "ordinary inquiries incident to a routine traffic
stop," id. at 338 (quotation omitted), and undertook his inves-
16                     UNITED STATES v. MUBDI
tigation expeditiously, completing the warning citation within
fifteen minutes.8

   The district court also correctly determined that the follow-
ing suspicious behavior supported York’s decision to extend
the investigation: (1) Mubdi took an excessive amount of time
to pull over; (2) he was exceedingly nervous; (3) he kept his
foot on the car brake instead of shifting the transmission into
park; (4) he could not provide details as to his destination or
the family member he intended to visit; (5) he did not rent the
car, contrary to what he told York; (6) he was not authorized
to drive the rental car; and (7) the car was beyond the bounds
authorized by the rental contract.

   Although some of these facts, viewed in isolation, might be
consistent with innocent travel, the Supreme Court has recog-
nized that such factors can, when taken together, give rise to
reasonable suspicion. United States v. Sokolow, 490 U.S. 1, 9
(1989) ("Any one of these factors is not by itself proof of any
illegal conduct and is quite consistent with innocent travel.
But we think taken together they amount to reasonable suspi-
cion."). Here, we have no trouble concluding that the circum-
stances supported York’s decision to extend the stop to
conduct the open-air canine sniff, which in turn alerted the
officers to the presence of contraband in the car.

   We have emphasized that reasonable suspicion "is not read-
ily, or even usefully, reduced to a neat set of legal rules, but,
rather, entails common sense, nontechnical conceptions that
deal with factual and practical considerations of everyday
life." United States v. Mason, 628 F.3d 123, 128 (4th Cir.
2010) (quoting Foreman, 369 F.3d at 781). As a reviewing
court, we "consider the totality of the circumstances and give
due weight to common sense judgments reached by officers
  8
   Wolfe arrived at the scene of the stop with his drug-sniffing dog while
York was issuing the warning citation, and thus the stop was not extended
because of any delay in the arrival of a canine unit.
                    UNITED STATES v. MUBDI                   17
in light of their experience and training." Id. (quotation omit-
ted). On this record, we decline to disturb the district court’s
order denying Mubdi’s motion to suppress.

                              III.

   Lastly, Mubdi argues that the district court violated his
Fifth and Sixth Amendment rights by increasing his statutory
mandatory minimum sentence for the drug offenses based on
improper judicial factfinding. Specifically, Mubdi contends
that the district court’s finding that he was responsible for
290.5 grams of crack cocaine violated his Fifth and Sixth
Amendment rights to have any fact that triggers an enhanced
mandatory minimum sentence charged in the indictment, sub-
mitted to a jury, and proved beyond a reasonable doubt. With-
out this finding, Mubdi argues that his guilty plea to crimes
involving at least fifty grams of crack cocaine would have
yielded only a ten-year mandatory minimum sentence. How-
ever, Mubdi acknowledges that Supreme Court precedent
forecloses this argument. See Harris v. United States, 536
U.S. 545, 568 (2002) (holding that increasing minimum sen-
tence based on judicial factfinding "does not evade the
requirements of the Fifth and Sixth Amendments").

   Accordingly, we affirm the district court’s imposition of a
240-month sentence for Mubdi’s drug convictions, which,
when combined with the sixty-month consecutive sentence
applied on the § 924(c) charge, properly yielded a 300-month
term of incarceration.

                              IV.

   For the foregoing reasons, we affirm the judgment of the
district court.

                                                   AFFIRMED
18                   UNITED STATES v. MUBDI
DAVIS, Circuit Judge, concurring in part and in the judg-
ment:

        Judicial narratives that begin with a traffic stop are
     notable for their depressing sameness. Because of
     the nature of our judicial system, these narratives are
     typically inscribed in criminal prosecutions. Usually
     only those on whom contraband is found are charged
     with crimes, and those charged with crimes have the
     strongest incentive to challenge the stop that led to
     the discovery of contraband. Absent unusual events,
     courts tend to uphold such searches, finding them
     supported by probable cause.

        There is no poetry in these narratives. They read
     like the documentation of an audit. The police go
     about their business. Courts double-check them. In
     most cases, the court finds the law enforcement offi-
     cers in compliance. In the process of all that process,
     we forget that–at least in criminal cases–someone’s
     freedom is on the line.

Nancy Leong, The Open Road and the Traffic Stop: Narra-
tives and Counter-Narratives of the American Dream, 64 Fla.
L. Rev. 305, 328 (2012) (footnotes omitted) (hereafter, "Open
Road").

   In Delaware v. Prouse, 440 U.S. 648 (1979), the Supreme
Court, applying the doctrine of Terry v. Ohio, 392 U.S. 1
(1968), definitively rejected, as inconsistent with the protec-
tions afforded by the Fourth Amendment, a claim to unfet-
tered discretion to stop and detain motorists on the part of law
enforcement officers seeking to uncover violations of the law:

        [W]e hold that except in those situations in which
     there is at least articulable and reasonable suspicion
     that a motorist is unlicensed or that an automobile is
     not registered, or that either the vehicle or an occu-
                       UNITED STATES v. MUBDI                          19
      pant is otherwise subject to seizure for violation of
      law, stopping an automobile and detaining the driver
      in order to check his driver’s license and the registra-
      tion of the automobile are unreasonable under the
      Fourth Amendment. This holding does not preclude
      the State of Delaware or other States from develop-
      ing methods for spot checks that involve less intru-
      sion or that do not involve the unconstrained
      exercise of discretion.

Id. at 663. Justice Rehnquist, dissenting, discerned "[no] suffi-
cient basis to distinguish for Fourth Amendment purposes
between a roadblock stopping all cars and the random stop"
at issue in the case before the Court. Id. at 667. He scoffed at
the majority’s determined effort to protect individual liberty,
accusing the majority of "elevat[ing] the adage ‘misery loves
company’ to a novel role in Fourth Amendment jurispru-
dence." Id. at 664.

   Seventeen years later, a unanimous Supreme Court effec-
tively vitiated the protections afforded by Prouse. In Whren
v. United States, 517 U.S. 806 (1996), the Court held that so
long as an officer can offer a plausible account that he had
probable cause a motorist committed a traffic infraction,
whether the motorist could be stopped and detained was a
matter entirely within the discretion of the officer.1 Despite
the potential for selective and discriminatory "traffic enforce-
ment," the officer’s "subjective intentions" in making the stop
play no role in Fourth Amendment analysis. In particular, as
the Court put it:

         We of course agree with petitioners that the Con-
      stitution prohibits selective enforcement of the law
      based on considerations such as race. But the consti-
      tutional basis for objecting to intentionally discrimi-
  1
   This circuit anticipated Whren’s holding in United States v. Hassan El,
5 F.3d 726, 729–31 (4th Cir. 1993), cert. denied, 511 U.S. 1006 (1994).
20                       UNITED STATES v. MUBDI
      natory application of laws is the Equal Protection
      Clause, not the Fourth Amendment. Subjective
      intentions play no role in ordinary, probable-cause
      Fourth Amendment analysis.

Id. at 813. See generally Wayne R. LaFave, The "Routine
Traffic Stop" from Start to Finish: Too Much "Routine," Not
Enough Fourth Amendment, 102 Mich. L. Rev. 1843 (2004).

   Over the ensuing sixteen years, judges,2 legal scholars,
social scientists, and many others have spilled much ink (and
the country has witnessed considerable political discourse)
exploring the ramifications of the Court’s about-face. Specifi-
cally, we have wrestled with the inevitable role that
constitutionally-permissible "pretextual" traffic stops play in
what the Court referred to as "ordinary, probable-cause Fourth
Amendment analysis," Whren, 517 U.S. at 813, in light of the
growth of racial profiling.3 Professor Leong has crafted a
cogent summary of the evolved legal regime:
   2
     See, e.g., Atwater v. City of Lago Vista, 532 U.S. 318, 372 (2001)
(O’Connor, J., dissenting) ("[A]s the recent debate over racial profiling
demonstrates all too clearly, a relatively minor traffic infraction may often
serve as an excuse for stopping and harassing an individual." (citing
Whren, 517 U.S. at 813)).
   3
     At an earlier time, some law enforcement officers freely employed the
term "pretextual stop" although, with increased sensitivity over racial pro-
filing, the term seems to have fallen from favor. See United States v. Fore-
man, 369 F.3d 776, 786-87 (4th Cir. 2004) (Gregory, J., concurring in part
and dissenting in part):
        Trooper Wade testified that he began to follow Foreman to
     "see if I could find a violation," id. at 30 (emphasis added), and
     admitted "[i]n an attempt to find a violation on [Foreman’s] vehi-
     cle . . . I was going to conduct a pretextual stop, stop him for a
     traffic violation, conduct a brief interview of him, see if I
     observed any indicators of other criminal activity . . . . " Id. at 60
     (emphasis added). Because Trooper Wade paced Foreman’s vehi-
     cle at a speed of sixty-four miles per hour over a one-half mile
     stretch of road where the speed limit was fifty-five, and observed
     "items hanging from the inside rearview mirror," he activated his
     emergency lights to make the stop, which Trooper Wade admit-
     ted was pretextual. See R. vol. 4 at 2.
                UNITED STATES v. MUBDI                      21
   Whatever all this means in the abstract world of
legal principles, the practical effect with respect to
traffic stops is that when the police think a driver has
committed any traffic violation, no matter how
minor or how fleeting, they can pull him over. Thus,
a driver might be pulled over for failing to signal for
an appropriate length of time or for changing lanes
too close to an intersection–things most of us rou-
tinely do on our daily commutes. The police can also
pull over a driver when they lack enough evidence
to establish probable cause of a violation if, under
Terry, they have reasonable suspicion that criminal
activity is afoot.

   These standards allow police officers to exercise
an enormous amount of discretion in performing
traffic stops. Under current doctrine, the legal justifi-
cation for stopping a car need not be the same as the
real reason the police officer wants to stop the car,
so long as a reasonable officer would have had prob-
able cause to believe that a traffic infraction in fact
took place. [Professor] Paul Butler [now of the
Georgetown University Law Center] describes riding
in a police cruiser with a police officer friend and
playing a game his friend invented called "Stop that
Car!" in which Butler "pick[s] a car–any car–and
[the officer] stops it." Butler explains that his friend
"is a good cop" because "[h]e waits until he has a
legal reason to stop the car. It doesn’t take long,
never more than three or four blocks of following.
There are so many potential traffic infractions that it
is impossible to drive without committing one." The
reality, then, is that the police are free to pick a car
they wish to stop, follow it until the driver inevitably
violates one of the vehicle code’s myriad obscure
provisions, and subsequently pull it over.

  The Supreme Court has repeatedly interpreted the
Constitution to permit this schism. Thus, even an
22                      UNITED STATES v. MUBDI
      officer with no actual purpose other than to harass
      and annoy may–according to the Supreme Court–use
      a traffic stop as an entirely constitutional starting
      point for such actions, as long as an objectively rea-
      sonable evaluation would conclude that the officer
      had probable cause to believe that a traffic violation
      occurred at the time she made the stop.

         From this starting point of an "objectively reason-
      able" stop supported by probable cause or reasonable
      suspicion, the judicial narrative then follows a well-
      worn script. Courts typically examine whether the
      circumstances justified the traffic stop, and–even
      more typically–answer that question in the affirma-
      tive. This is so even when the events of the traffic
      stop stray beyond its ostensible justification. The
      Court has explained: "An officer’s inquiries into
      matters unrelated to the justification for the traffic
      stop . . . do not convert the encounter into something
      other than a lawful seizure, so long as those inquiries
      do not measurably extend the duration of the stop."

Open Road at 326-27 (footnotes omitted).4
  4
   For a sampling of some of the more recent literature in this genre, see
Thomas B. McAffee, Setting Us Up For Disaster: The Supreme Court’s
Decision in Terry v. Ohio, 12 Nev. L.J. 609, 614-15 (2012) ("The further
we go along, the clearer it becomes that there is widespread ‘racialized
policing,’ what we have labeled as ‘racial profiling,’ and that its pervasive
presence is so important in part because it is measurable . . . . The wide
use of racial profiling is reinforced by Terry’s holding as well as by the
way the suspicion standard has been expansively applied over time.")
(footnotes omitted); Eric J. Miller, Detective Fiction: Race, Authority and
the Fourth Amendment, 44 Ariz. St. L.J. 213, 220 (2012) (observing that
"the Court is aware (through both dissenting opinions and some hints in
recent majority opinions) that its jurisprudence is driven by the War on
Drugs, and that the style of policing it endorses to fight that war is dragnet
and racialized, and that the success rate for this style of policing is low")
(footnotes omitted); Mary D. Fan, The Police Gamesmanship Dilemma in
                        UNITED STATES v. MUBDI                             23
   Of course, the four-decades-and-counting "War on Drugs"
has given a special context and meaning to the Whren doc-
trine and its implications for racial profiling. Beyond their
undoubtedly sincere desire to do their jobs and to do them
well and safely, local law enforcement officers and their
employing agencies, such as the Statesville police department
involved in this case, have serious skin in the drug interdic-
tion game, no matter the ultimate destination of the contra-
band. See, e.g., Ricardo J. Bascuas, Fourth Amendment
Lessons from the Highway and the Subway: A Principled
Approach to Suspicionless Searches, 38 Rutgers L.J. 719,
761-62 (2007) (discussing profits made by police from drug
interdiction programs). It was not for nothing that officers
York and Wolfe, each with a drug canine in his vehicle,
started their shifts before nine in the morning sitting perpen-
dicular to I-77 watching traffic, deciding which of the many
vehicles passing them by they would follow and stop, abjur-
ing the use of the speed radar devices.5 Likewise, it was not

Criminal Procedure, 44 U.C. Davis L. Rev. 1407, 1463 (2011) ("In the
decade since Whren, therefore, the problem of profiling has persisted
while Whren stands as a controversial landmark of noninquiry and ‘a
license to make racial distinctions.’ Whren is a lightning rod for contro-
versy because the Court took a don’t ask, don’t tell approach allowing
police to do whatever it takes—without examining the accuracy of police
beliefs about what it takes, basing deference on noninquiry rules rather
than data.") (footnotes omitted); see also Bernard E. Harcourt, Rethinking
Racial Profiling: A Critique of the Economics, Civil Liberties, and Consti-
tutional Literature, and of Criminal Profiling More Generally, 71 U. Chi.
L. Rev. 1275 (2004).
   5
     Insisting that the Statesville police were engaged in "criminal interdic-
tion" and not merely "drug interdiction" at the time of the stop in this case,
the officers’ supervisor, Captain Dyson, testified at the suppression hear-
ing that York and Wolfe were "looking for criminals" who might be driv-
ing north on I-77 that morning. J.A. 126. The cross-examination of Dyson
included the following:
      Q. So how do you determine whether a motorist is a criminal
    or not?
24                      UNITED STATES v. MUBDI
for nothing that, as shown on the video taken by the dash-
board camera in York’s vehicle, the officers in this case
expressed unmitigated glee, punctuated by serial "fist-bumps"
all around, when the cache of more than two hundred grams
of crack cocaine was removed from the Dodge Magnum.

   All that said, this court has done (and will continue to do)
what it can to hold true the line between excessive law
enforcement zeal that transgresses constitutional limits, on the
one hand, and legitimate law enforcement techniques respect-
ful of constitutional constraints, on the other hand. See, e.g.,
United States v. Digiovanni, 650 F.3d 498 (4th Cir. 2011)
(affirming district court’s grant of motion to suppress evi-
dence seized after a traffic stop). At the constitutional mar-
gins, of course, one may yet legitimately question why, as
Professor Leong correctly observed (and especially as the
government bears the burden of proof), close calls seem
always to go to law enforcement. See, e.g., United States v.
Mason, 628 F.3d 123, 132 (4th Cir. 2010) (holding that ques-
tioning of motorist and passenger unrelated to the basis for the
traffic stop that took "one to two minutes" did not render stop
unreasonable because the stop was conducted "promptly and
with efficiency"); but see id. at 134-35 (Gregory, J., dissent-
ing) (disagreeing that duration of stop was reasonable, where
detaining officer described African-American occupants of
stopped car as "spooky spooky" and officer’s testimony

        A. There’s a bunch of things you look at. You look at criminal
     indicators when they’re coming by. How they position them-
     selves when they come by. The expression they might give or the
     expression they don’t give. Or when they come by, somebody
     might just turn up a drink all of a sudden for no reason. Or when
     they come by – you’re sitting there watching traffic. All of a sud-
     den when the car comes by, they all of a sudden take their hand
     and cover their face when they come by. It’s something that
     draws your attention to them. But you’re also looking for a motor
     vehicle violation.
J.A. 128.
                        UNITED STATES v. MUBDI                             25
sought to justify reasonable suspicion based on officer’s "ex-
perience" and "sort of gut instinct"). To be sure, given the rel-
ative institutional competencies between district and circuit
courts, and given the controlling standards of review of sup-
pression rulings, see ante 7, trial judges, not the judges of this
court, have the primary role in policing the police.

   Our recent decision in United States v. Sowards, ___ F.3d
___, 2012 WL 2386605 (4th Cir. June 26, 2012), is wholly
consistent with our on-going efforts; it lays down an impor-
tant marker that there are indeed limits to the scope of law
enforcement creativity inherent in the otherwise standardless
Whren doctrine. Unlike the majority here, however, I cannot
identify any material differences in the facts at hand that will
support a difference in outcome between this case and the out-
come in Sowards on the issue of uncorroborated visual speed
estimates, although I fully agree that Sowards does not sound
the death knell to the use of visual speed estimates by law
enforcement officers.6 Accordingly, as to the justification for
the vehicle stop in this case, I join only Part II.A.2 of the
majority opinion, which, as an alternative holding, sustains
the district court’s determination that the ostensible
following-too-closely violation supported the existence of
probable cause to effect the vehicle stop here. I also concur
in Parts I, II.B., and III of the majority opinion, and in the
judgment.
   6
     Interestingly, the evidence at the suppression hearing, including the
officers’ testimony and images from the video taken by York’s dashboard
camera, indicated that over the approximately five miles during which
officers York and Wolfe surveilled Mubdi after they first observed the
Dodge Magnum, the posted speed limits on I-77 and I-40 increased from
fifty-five miles per hour (where the officers first observed Mubdi), to sixty
miles per hour, to sixty-five miles per hour at the location where the traffic
stop was finally effected. Apparently, the officers set up their "criminal
interdiction" operation, in which visual estimates of vehicle speeds played
a major role, at an optimal location to stop vehicles traveling more than
the posted fifty-five mile per hour limit, and just before the limit increased
to sixty, and then to sixty-five, miles per hour.
