                 FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,                 No. 04-10079
                Plaintiff-Appellee,          D.C. No.
               v.                         CR-03-00157-
MARK LAMOND WILLIS,                         PMP/LRL
             Defendant-Appellant.
                                           OPINION

       Appeal from the United States District Court
                for the District of Nevada
         Philip M. Pro, District Judge, Presiding

                 Argued and Submitted
       December 8, 2004—San Francisco, California

                 Filed December 19, 2005

      Before: Alex Kozinski, William A. Fletcher, and
               Jay S. Bybee, Circuit Judges.

                Opinion by Judge Bybee;
               Dissent by Judge W. Fletcher




                           16549
                UNITED STATES v. WILLIS         16551


                     COUNSEL

Anne R. Traum, Assistant Federal Public Defender, Las
Vegas, Nevada, for the defendant-appellant.
16552               UNITED STATES v. WILLIS
Andrew W. Duncan (argued) and Thomas S. Dougherty,
Assistant United States Attorneys, Las Vegas, Nevada, for the
plaintiff-appellee.


                           OPINION

BYBEE, Circuit Judge:

   Appellant Mark Lamond Willis appeals the denial of his
motion to suppress evidence following his conditional guilty
plea for violation of 18 U.S.C. §§ 922(g) and 924(a)(2), felon
in possession of a firearm and forfeiture of the firearm. Willis
moved to suppress the firearm found in his possession as the
fruit of an illegal seizure. See U.S. CONST. amend. IV. Finding
his arguments unpersuasive, we affirm the district court’s
denial of the motion to suppress evidence and affirm Willis’s
conviction.

                                I

    On December 19, 2002, around 2:00 a.m., Las Vegas Met-
ropolitan Police Department (“LVMPD”) Officer Carl Boeh-
mer “observed a [white two-door] vehicle turning rapidly onto
Las Vegas Boulevard . . . .” Officer Boehmer testified that the
vehicle’s rapid turn attracted his attention because “[i]t was
just a more excessive turn than a citizen should [make].” He
followed the vehicle as it made two more quick turns before
stopping in front of an apartment building in a high-crime
area. Officer Boehmer then watched a male (later identified
as Willis) get out of the car, sprint across the street and up the
stairs to the second floor of an apartment building, and pound
on the door until he was admitted into one of the apartments.
When Officer Boehmer drove past the vehicle, he noticed that
Willis had left the windows down, which he thought was
unusual because there are “many stolen vehicles in that area
. . . [and] gang activity . . . .” He then ran a check on Willis’s
                       UNITED STATES v. WILLIS                      16553
Colorado license plate, and notified his dispatch unit to
request a backup unit.

   The LVMPD Communications Center informed Officer
Boehmer that the car was listed as a “suspicious vehicle” and
that there was a National Crime Information Center (“NCIC”)
missing person’s report or “hit” associated with the license
plate.1 After receiving this information, Officer Boehmer
positioned himself in an alley where he could watch the car
and the apartment. Shortly thereafter, Officer D. Miller
arrived, and as Officer Boehmer was describing the situation,
Willis exited the apartment, reentered his vehicle, made an
illegal U-turn, and drove a short distance before pulling over
in front of a second apartment complex a block or two away.
Officers Boehmer and Miller each made U-turns, turned on
their overhead lights, and boxed in Willis’s car.

   As the officers parked their vehicles, Willis stepped out of
his car and looked nervously from side-to-side at the patrol
cars. Officer Boehmer testified that he believed that Willis
was contemplating running away, and he ordered Willis to
step in front of the vehicle and show his hands. Officer Boeh-
mer testified that he “immediately began ordering commands
to him to step to the front of my vehicle, and also to take his
hands out of his pockets because at the time he had his hands
in his jacket pockets. . . . [F]rom my experience again, some-
one that . . . immediately opens up their vehicle and jumps out
and begins looking side to side pretty frantically is, in my
experience they’ve always taken off running. So before . . .
he had a chance to, I just started giving commands.”
  1
   The NCIC is “a national criminal records data system administered by
the Federal Bureau of Investigation. See 28 U.S.C. § 534. NCIC contains
criminal history information, including outstanding arrest warrants, and is
available to police departments nationwide. State law enforcement agen-
cies are connected to NCIC through their computer systems.” Case v. Kit-
sap County Sheriff’s Dep’t, 249 F.3d 921, 923-24 (9th Cir. 2001).
16554                  UNITED STATES v. WILLIS
   Willis complied, and as Officer Boehmer approached him,
Officer Boehmer asked, “Do you have anything on you I
should know about?” Willis replied, “Yes, I do.” When Offi-
cer Boehmer asked “what is it?”, Willis answered: “a gun.”
Officer Miller requested permission from Willis to look inside
his pockets, which Willis gave, and the officer retrieved a
fully loaded .25 caliber handgun from Willis’s jacket.

   Officer Boehmer questioned Willis about the firearm while
Officer Miller “proceeded to take care of the missing per-
son[’s report].” Willis explained to the officers that the person
identified in the report was his girlfriend and that she was in
his apartment.2 Officer Miller conducted an interview with
Willis’s girlfriend upstairs in the apartment complex. Officer
Boehmer testified that “she was okay, and she stated that she
had talked with her family and it [the NCIC missing person’s
report] needed to be cleared out of the system.”

   Willis admitted to the officers that he had been convicted
of crimes in Hawaii and Colorado. Officer Boehmer con-
firmed this through a criminal history check, and he arrested
Willis for being an “ex-felon in possession of a firearm, carry-
ing a concealed weapon, [and] ex-felon failure to register.”

   Willis moved to suppress the evidence of the handgun. He
argued that the officers had violated his Fourth Amendment
rights by detaining and searching him, and that the evidence
   2
     LVMPD officers had stopped Willis and his girlfriend a week earlier,
on December 12, in response to the NCIC report. During that encounter,
police questioned Willis about the missing person’s report and determined
that Willis’s girlfriend was not in any danger. LVMPD requested that the
Escondido Police Department (“EPD”), which issued the report, call and
confirm that the missing person’s report was still current. EPD confirmed
the report, and asked LVMPD to send a “locate,” which is information
stating that the missing person has been located in the area. LVMPD con-
tacted Willis’s girlfriend’s family and EPD to give them information about
her, but the record does not indicate when or if LVMPD sent the requested
“locate” to EPD.
                        UNITED STATES v. WILLIS                        16555
of the handgun was the illegal fruit of that detention and
search. The magistrate judge concluded in his report and rec-
ommendation that the officers had no “reasonable articulable
suspicion . . . of criminal activity” to justify an investigatory
Terry stop. See Terry v. Ohio, 392 U.S. 1, 20-22 (1968). How-
ever, the magistrate judge found that “[u]nder these circum-
stances . . . Officer Boehmer’s community caretaking function
required him to take reasonable steps in an effort to determine
the current status of the alleged missing person. His failure to
do so would have amounted to a dereliction of duty.”

   The district court adopted the magistrate judge’s report and
recommendation over Willis’s objections. Willis entered a
conditional guilty plea, preserving his objection to the denial
of his motion to suppress the evidence recovered during the
search. The district court sentenced Willis to a term of thirty-
three months imprisonment. Willis appeals the denial of his
motion to suppress.3

                                      II

    Willis argues that neither the community caretaking func-
tion nor the related emergency aid doctrine justified his sei-
zure. He also argues that the police officers did not have
reasonable suspicion for the stop, and that the government
waived its arguments advocating reasonable suspicion when
it failed to object to the findings of the magistrate judge’s report.4
  3
     We review the district court’s denial of Willis’s motion to suppress
evidence de novo; the district court’s factual findings are reviewed for
clear error. See United States v. Fernandez-Castillo, 324 F.3d 1114, 1117
(9th Cir. 2003).
   4
     Willis argues that the government waived its reasonable suspicion
argument by failing to present it to the district court when the district court
adopted the magistrate judge’s report and recommendation denying Wil-
lis’s motion to suppress. See In re Grand Jury Subpoena (Mark Torf/Torf
Environmental Management), 357 F.3d 900, 910 (9th Cir. 2004). Here, the
government prevailed before the magistrate judge. A party prevailing
before a magistrate judge need not object to the magistrate’s report and
16556                   UNITED STATES v. WILLIS
We decline to determine whether the community caretaking
function, or the emergency aid doctrine, justified the officers’
detention of Willis. Instead, we hold that the detention came
within the scope of a valid traffic stop, because Officer Boeh-
mer had at least reasonable suspicion—if not probable cause
—to stop Willis for violating the traffic laws. See Whren v.
United States, 517 U.S. 806, 810 (1996) (“As a general mat-
ter, the decision to stop an automobile is reasonable where the
police have probable cause to believe that a traffic violation
has occurred.”); see also Berkemer v. McCarty, 468 U.S. 420,
439 (1984) (“the usual traffic stop is more analogous to a so-
called ‘Terry stop’ than to a formal arrest”; holding that a traf-
fic stop requires reasonable suspicion (internal citation omit-
ted)); United States v. Lopez-Soto, 205 F.3d 1101, 1104-05
(9th Cir. 2000) (“the Fourth Amendment requires only rea-
sonable suspicion in the context of investigative traffic stops”;
holding that “the Court in Whren [did not] intend[ ] to change
this settled rule”). Since Willis’s detention was supported by
reasonable suspicion, the officers could reasonably question
Willis to ensure their own safety. Once Willis admitted pos-

recommendation in order to preserve its right to argue an alternative the-
ory in support of the recommendation on appeal. See Britt v. Simi Valley
Unified Sch. Dist., 708 F.2d 452, 454 (9th Cir. 1983) (“The language of
[28 U.S.C. § 636(b)(1)] does not indicate that failure to object to a magis-
trate’s recommendation will be an absolute bar to appeal from the district
court’s decision.”), overruled on other grounds, United States v. Reyna-
Tapia, 328 F.3d 1114, 1121-22 (9th Cir. 2003) (en banc). But cf. McCall
v. Andrus, 628 F.2d 1185, 1187 (9th Cir. 1980) (holding that waiver is
appropriate where a party’s failure to object to the magistrate judge’s con-
clusions of law was coupled with its failure to raise the objection until its
reply brief); Schmidt v. Johnstone, 263 F. Supp. 2d 1219, 1222-24 (D.
Ariz. 2003) (noting a possible intra-circuit conflict on whether a failure to
object to a magistrate’s conclusions of law waives the right to appeal
them). Although Britt and McCall are to some degree in tension, Britt’s
core holding—that a prevailing party need not object to a magistrate
judge’s conclusions of law in order to preserve those grounds for appeal—
remains good law, at least where the objections are raised on appeal in
either the prevailing party’s opening or answer brief. See 28 U.S.C.
§ 636(b)(1).
                     UNITED STATES v. WILLIS                 16557
sessing the weapon, the officers’ search to relieve Willis of
his weapon was also reasonable.

                                 A

   [1] “The Fourth Amendment prohibits ‘unreasonable
searches and seizures’ by the Government, and its protections
extend to brief investigatory stops of persons or vehicles that
fall short of traditional arrest.” United States v. Arvizu, 534
U.S. 266, 273 (2002) (citing United States v. Cortez, 449 U.S.
411, 417 (1981); Terry v. Ohio, 392 U.S. 1, 9 (1968)). Such
investigatory stops are justified by “reasonable suspicion” that
criminal activity may be afoot. Arvizu, 534 U.S. at 273; see
also United States v. Sokolow, 490 U.S. 1, 7 (1989); Cortez,
449 U.S. at 417. “[T]he Fourth Amendment’s proper function
is to constrain, not against all intrusions . . . but against intru-
sions which are not justified in the circumstances, or which
are made in an improper manner.” Schmerber v. California,
384 U.S. 757, 768 (1966). The “touchstone of the Fourth
Amendment is reasonableness. The Fourth Amendment does
not proscribe all state-initiated searches and seizures; it
merely proscribes those which are unreasonable.” Florida v.
Jimeno, 500 U.S. 248, 250 (1991) (citations omitted).

   [2] Although we look to reasonableness in determining the
propriety of a stop under the Fourth Amendment, the Supreme
Court’s decision in Whren v. United States does not require
us to determine the reasonableness of a temporary detention
if there is reasonable suspicion to conclude that a traffic viola-
tion occurred. Whren, 517 U.S. at 818-19. In Whren, a unani-
mous Supreme Court held that a stop was reasonable under
the Fourth Amendment where officers had probable cause to
believe that the petitioner violated the traffic code, even if the
ultimate charge was not related to the traffic stop. Id. at 808-
09. Police observed a truck in a “high drug area” stopped at
stop sign for an excessive amount of time, which then turned
without signaling and sped off at an excessive speed. Id. at
808. Once the police caught up to the vehicle, the officers
16558               UNITED STATES v. WILLIS
observed Michael Whren, one of the passengers, holding two
large bags of what appeared to be crack cocaine. Whren
argued that the stop had not been justified by probable cause
to believe that the occupants were engaged in illegal drug
activity, and that the officers’ asserted ground for approaching
the vehicle, which was to give them a warning about traffic
violations, was pretextual. Id. at 809.

   The Supreme Court held that the officers had probable
cause to believe that various provisions of the traffic code had
been violated. Id. at 810. The Court specifically declined to
hold that the Fourth Amendment test for traffic stops should
be “whether a police officer, acting reasonably, would have
made the stop for the reason given.” Id. Rather, the Court
explained that “[s]ubjective intentions play no role in ordi-
nary, probable-cause Fourth Amendment analysis,” and that
“we have been unwilling to entertain Fourth Amendment
challenges based on the actual motivations of individual offi-
cers.” Id. at 813. Whren stands for the proposition that if the
officers have probable cause to believe that a traffic violation
occurred, the officers may conduct a traffic stop even if the
stop serves some other purpose. See also Devenpeck v. Alford,
125 S. Ct. 588, 593-94 (2004) (“[The] subjective reason for
making the arrest need not be the criminal offense as to which
the known facts provide probable cause.”).

   [3] There is ample evidence that the officers had at least
reasonable suspicion to stop Willis for his traffic violations.
First, Officer Boehmer testified that he watched Willis make
an illegal U-turn on Hoover. Second, Officer Boehmer testi-
fied that he watched Willis make a rapid turn, stating, “It was
a traffic violation being that it was a turn — making a turn
more excessive than it should have been [and] . . . it would
have been a municipal traffic code [violation].” Third, accord-
ing to testimony by Officer Boehmer, Willis’s car also
appeared to accelerate excessively. Cf. Whren, 517 U.S. at
808 (police stopped car after it “turned suddenly to its right,
without signaling, and sped off at an ‘unreasonable’ speed.”)
                        UNITED STATES v. WILLIS                       16559
Officer Boehmer specifically noted that after he observed the
rapid turn, “I was going to follow him to see if he had made
any other — other traffic violations . . . .” (emphasis added).
It is clear from Officer Boehmer’s testimony that he observed
several traffic violations, including driving too fast, rapid
turns, and an illegal U-turn.5

   The fact that Willis had parked his car at the point that the
officers detained him does not affect our analysis. Officer
Boehmer did not stop Willis immediately after he first noted
Willis’s traffic violations, but followed the car to “see if [Wil-
lis] made any other traffic violations.” Moreover, any delay
between Willis’s traffic violations and the officers’ actions
was insignificant. The officers detained Willis as soon as they
observed him pull over.

   [4] Under Whren, we cannot second-guess the reasons for
the officer’s stop. Whren, 517 U.S. at 813 (“Subjective inten-
tions play no role in ordinary, probable-cause Fourth Amend-
ment analysis.”).6 Indeed, the Supreme Court recently
  5
     The dissent purports to take Officer Boehmer at his word, see Dissent
at 16564, but then proceeds to doubt his observation that Willis committed
traffic infractions. See id. at 16569-70, 16575-77. The dissent’s doubts are
based on the fact that the officer did not provide information such as the
posted speed limit, the exact speed Willis was traveling or whether the
incident occurred in a business district. But the officer has satisfied the
government’s burden of production by coming forward with “specific and
articulable facts,” Terry, 392 U.S. at 21, to support his suspicion of illegal
activity. The defendant has the burden of proof on a motion to suppress
evidence, see United States v. Caymen, 404 F.3d 1196, 1199 (9th Cir.
2005), and if Willis wanted to cast doubt on Officer Boehmer’s statement
that his erratic behavior constituted a traffic infraction, he was required to
introduce contrary evidence or get the officer to retract his testimony on
cross-examination. Defendant did neither, so Officer Boehmer’s testimony
that he observed Willis committing traffic infractions stands unrefuted.
   6
     The dissent relies on the fact that the magistrate judge “found that the
officers did not have a reasonable suspicion of criminal activity that would
justify a [Terry] stop.” Dissent at 16563. The magistrate judge found, in
pertinent part, as follows:
16560                   UNITED STATES v. WILLIS
affirmed this proposition in Devenpeck: “Our cases make
clear that an arresting officer’s state of mind (except for the
facts that he knows) is irrelevant to the existence of probable
cause.” 125 S. Ct. at 593-94. Therefore, as long as “the offi-
cers had probable cause to believe that [Willis] had violated
the traffic code[,] . . . the stop [was] reasonable under the
Fourth Amendment.” Whren, 517 U.S. at 819. The officer tes-
tified that he was planning on conducting a vehicle stop “be-
cause of the information of the NCIC missing person . . .
[and] because of the way the vehicle was evading me and
conducting an illegal U-turn also, in the middle of Hoover.”
Since Officer Boehmer could have relied on the traffic viola-

    Here, the court finds that the totality of the circumstances
    described by Officer Boehmer did not give rise to a “reasonable
    articulable suspicion” that Willis was engaged in or about to
    engage in some identifiable form of criminal activity. Although
    Boehmer may have seen Willis exceeding the speed limit, the
    reason Boehmer wanted to stop him was not to issue a traffic
    citation; it was to inquire into the circumstances giving rise to the
    NCIC missing person hit.
To the extent the magistrate judge made the same mistake as the dissent,
by finding reasonable suspicion for a traffic stop lacking based on the offi-
cer’s subjective motivations, we reverse. The parsing of police motives —
as opposed to “articulable facts,” Terry, 392 U.S. at 21 — is precisely
what Whren tells us we may not do. See Whren, 517 U.S. at 811 (refusing
to “endors[e] the principle that ulterior motives can invalidate police con-
duct that is justifiable on the basis of probable cause to believe that a vio-
lation of law has occurred”).
   Nor need we remand to establish the basis for a Terry stop. See Dissent
at 16577-78. The magistrate judge made a factual finding after an eviden-
tiary hearing that Willis “made a U-turn on Hoover.” Officer Boehmer tes-
tified that this turn was illegal, and his testimony is unrefuted. The
magistrate judge’s statement that “[t]he court need not assess the credibil-
ity of the officer’s testimony about Willis’s driving” presumably refers
only to Officer Boehmer’s testimony that Willis was traveling at an exces-
sive rate of speed, since the excessive speed allegation — unlike the fact
that Willis “made a U-turn on Hoover” — was not part of the magistrate
judge’s factual findings. Because the illegal U-turn was sufficient to jus-
tify the traffic stop, no remand is required.
                        UNITED STATES v. WILLIS                        16561
tion as a justification for stopping Willis, the stop was valid
under Whren.7

   The dissent argues that Willis’s detention was not a traffic
stop because “Officer Boehmer never mentioned any traffic
violation or issued any traffic citation.” Dissent at 16576. But
Officer Boehmer explained that by the manner in which Wil-
lis exited his car, Boehmer thought Willis was about to run.
It was in the ensuing quick exchanges between Boehmer and
Willis that Boehmer discovered that Willis was armed and
arrested him. We think it was reasonable for the officers to
view any traffic violations as inconsequential in light of Wil-
lis’s arrest. Whren and Lopez-Soto require that the officers
have reasonable suspicion to stop a driver for traffic infrac-
tions, not that the officers issue citations.8

                                      B

   [5] Once the police stopped Willis, they could, within rea-
son, search the area and question Willis about weapons for
their own safety. “Police officers are entitled to employ rea-
sonable methods to protect themselves and others in poten-
tially dangerous situations.” Allen v. City of Los Angeles, 66
F.3d 1052, 1056-57 (9th Cir. 1995) (citing United States v.
  7
     Willis also argues that the evidence seized in the stop should be
excluded because the police had stopped Willis the week before based on
the same NCIC report. We find no basis for excluding the evidence. There
is nothing in the record that shows Officers Boehmer and Miller were
aware that the NCIC missing person’s report was outdated, nor is there
evidence that the LVMPD deliberately failed to send a “locate” to the
Escondido Police Department. In any event, because the officers had at
least reasonable suspicion to stop Willis for a traffic violation, the validity
of any other reasons they may have had to stop him becomes irrelevant.
   8
     Indeed, in Whren, the plainclothes vice officer who stopped Whren
after observing apparent traffic violations testified that “he did not intend
to issue a ticket to the driver for stopping too long at the stop sign, but he
wished to stop the Pathfinder to inquire why it was obstructing traffic and
why it sped off without signalling in a school area.” United States v.
Whren, 53 F.3d 371, 373 (D.C. Cir. 1995), aff’d, 517 U.S. 806 (1996).
16562               UNITED STATES v. WILLIS
Jacobs, 715 F.2d 1343, 1345-46 (9th Cir. 1983)). Our cases
have justified the use of force in making a stop if it occurs
under circumstances justifying fear for an officer’s personal
safety. See Jacobs, 715 F.2d at 1345-46; United States v.
Beck, 598 F.2d 497, 501 (9th Cir. 1979). In this case, Officer
Boehmer merely asked Willis if he had anything that Officer
Boehmer should know about. He did not take more extreme
measures, but simply asked Willis a question to ensure the
officers’ personal safety. Officer Boehmer did not act unrea-
sonably in ensuring his personal safety and the safety of his
fellow officer. Indeed, even before Officer Boehmer was noti-
fied about the NCIC hit, he requested backup for his own
safety. As he testified, “I notified dispatch on the radio that
I was requesting a backup unit. . . . For officer safety. Due to
the suspicious situation, the known gang, prostitution and
drug activity in the area . . . for officer safety, I wanted
another officer there, and the time of night.”

   [6] Given everything that the officers knew, including the
NCIC hit, Willis’s erratic driving, the high-crime area, and
Willis’s nervous and agitated state, Officer Boehmer’s ques-
tion to Willis eliciting information about Willis’s gun was
reasonable. Once Willis informed the officers that he was car-
rying a firearm, the officers were entitled to seize the firearm
in order to avoid any possibility that Willis would use it
against them. The evidence of possession of a firearm was not
the fruit of an illegal search, and the evidence need not have
been suppressed.

                              III

  The district court’s denial of the motion to suppress the evi-
dence is affirmed. Willis’s conviction is affirmed.

  AFFIRMED.
                    UNITED STATES v. WILLIS               16563
W. FLETCHER, Circuit Judge, dissenting:

   In his Report and Recommendation, the magistrate judge
found that because defendant Mark Willis had already volun-
tarily stopped his car, Officers Carl Boehmer and D. Miller
did not perform a traffic stop under Whren v. United States,
517 U.S. 806 (1996). Because the magistrate judge found that
there had been no traffic stop, he specifically declined “to
assess the credibility of the officer’s testimony about Willis’s
driving.” The magistrate judge further found that the officers
did not have a reasonable suspicion of criminal activity that
would justify a stop under Terry v. Ohio, 392 U.S. 1 (1968).
However, the magistrate judge found that the stop was justi-
fied by the community caretaking function under Cady v.
Dombrowski, 413 U.S. 433 (1973). In denying Willis’s
motion to suppress, the district court adopted without change
the Report and Recommendation.

  The majority declines to affirm the district court’s decision
based on either Terry or Cady. Instead, it affirms on a ground
explicitly rejected by the magistrate judge and the district
court — that Officers Boehmer and Miller performed a per-
missible traffic stop under Whren. For two independent rea-
sons, I respectfully dissent.

   First, Officer Boehmer was required to present “specific,
articulable facts” to support his contention that there was rea-
sonable suspicion that Willis had violated the traffic laws, and
thereby to justify a traffic stop under Whren. Terry, 392 U.S.
at 21; United States v. Michael R., 90 F.3d 340, 346 (9th Cir.
1996). Despite ample opportunity, he did not do so. Second,
Whren applies only to “run-of-the-mine” traffic stops. 517
U.S. at 819. The stop at issue in this case was anything but
“run-of-the-mine,” and therefore does not qualify as a traffic
stop under Whren.

                           I.   Facts

   Only two people testified at the suppression hearing before
the magistrate judge, Officer Boehmer of the Las Vegas Met-
16564               UNITED STATES v. WILLIS
ropolitan Police Department, and defendant Willis. The mag-
istrate judge wrote that he “need not assess the credibility of
the officer’s testimony about Willis’s driving” because he
found that no traffic stop occurred, given that “Willis volun-
tarily pulled his car over in front of his own residence before
Officers Boehmer and Miller swooped in and surrounded
him.” (Emphasis in original.) For purposes of my dissent, I
assume that Officer Boehmer testified truthfully about what
he saw and thought he saw.

   As will be apparent, there are two problems with Officer
Boehmer’s testimony. First, as to his justification for the traf-
fic stop, the problem is not with what Officer Boehmer stated.
Rather, the problem is what he did not state. That is, Officer
Boehmer’s testimony does not contain sufficient “specific,
articulable facts” to justify a traffic stop. See Terry, 392 U.S.
at 21, Michael R., 90 F.3d at 346. Second, as to the nature of
the stop, Officer Boehmer’s testimony makes clear that his
detention of Willis was anything but a “run-of-the-mine” traf-
fic stop. Because it was not such a traffic stop, it cannot be
justified under Whren.

                     A.    Willis’s Driving

   Early in the morning of December 19, 2002, Willis, an
African-American male, was driving a car with Colorado
license plates within the city limits of Las Vegas, Nevada.
Officer Boehmer testified that he began to follow Willis in a
marked patrol car after seeing him make a “rapid turn” from
Hoover Avenue right onto Las Vegas Boulevard. Officer Boe-
hmer testified at the hearing that three aspects of Willis’s
driving warranted a stop for traffic violations — his “rapid
turn” onto Las Vegas Boulevard, his accelerating and speed-
ing after that turn, and his later U-turn on Hoover Avenue. I
consider them in sequence.

                      1.    “Rapid Turn”

  Officer Boehmer testified that the “rapid turn” onto Las
Vegas Boulevard from Hoover Avenue was “more excessive
                    UNITED STATES v. WILLIS                16565
than it should have been,” and that he believed this turn vio-
lated the traffic laws. Officer Boehmer elaborated in an
exchange with the magistrate judge:

    Q: What do you mean that the turn is more exces-
    sive than it should have been?

    A: Well, the speed is more excessive than I’d say
    operating speed would be.

    Q:    All right. What is the traffic code violation?

    A:    I don’t know, Your Honor.

    Q:    No citation was issued in this case?

    A:    No.

    Q: Do you have any idea what — I mean, is there
    — this was in the city of Las Vegas and would have
    been under the — either the state’s —

    A: It would have been — it would have been a
    municipal traffic code. Yes, Your Honor.

    Q: Okay. And you don’t know what the traffic
    code would be?

    A: No, Your Honor. I don’t really write too many
    tickets.

    Q:    Okay.

    A:    I just mostly do criminal investigations.

     2.   Accelerating and Exceeding the Speed Limit

  Officer Boehmer testified that after turning right onto Las
Vegas Boulevard, Willis turned right onto Charleston Boule-
16566               UNITED STATES v. WILLIS
vard, turned right onto Third Street, and finally turned right
back onto Hoover Avenue. The distance on Las Vegas Boule-
vard between Hoover Avenue and Charleston (i.e., between
Willis’s first and second turns) is one block. The distance on
Charleston between Las Vegas Boulevard and Third Street
(i.e., between his second and third turns) is two blocks. The
distance on Third Street between Charleston and Hoover (i.e.,
between his third and fourth turns) is a block and a half. After
his fourth right turn back onto Hoover, Willis parked his car
on the south side of the street at or near the northwest corner
of Third and Hoover. Willis traveled essentially in a circle,
covering a total distance of somewhere between four-and-a-
half and five blocks.

   On direct, Officer Boehmer testified that he was driving
northbound on Fourth Street at the intersection of Fourth and
Hoover when he first saw Willis. Officer Boehmer was one
block away from Willis, who at that moment was making his
“rapid” right turn from Hoover onto Las Vegas Boulevard.
Officer Boehmer testified that he turned right onto Hoover
toward Las Vegas Boulevard to follow Willis. Then, as Offi-
cer Boehmer turned right onto Las Vegas Boulevard from
Hoover, he saw Willis — still one block ahead of him —
turning right onto Charleston. Officer Boehmer testified, “I
accelerated to attempt to catch up with the vehicle because it
was apparent to me, with the distance he had gained, he had
been accelerating. I then made a westbound turn onto Charles-
ton, and at the time the vehicle was just beginning to make a
turn onto northbound Third Street.” Boehmer testified that in
his opinion Willis was trying to evade him. He said, “Just
from my experience — my three years experience, in the past
people trying to evade me, make rapid continuous turns like
that.”

  On further questioning by the magistrate judge, Officer
Boehmer reiterated his view that Willis’s right turn onto Las
Vegas Boulevard had been a traffic violation. He also stated
                    UNITED STATES v. WILLIS               16567
for the first time that, although he could not tell “exactly how
fast” Willis was traveling, he was exceeding the speed limit:

    Q: [A]s you reached Hoover, to your right you
    looked and saw this white vehicle making a right
    turn from Hoover onto Las Vegas Boulevard south-
    bound?

    A:   Yes. Yes, Your Honor.

    Q:   A rapid turn?

    A:   Yes, a rapid turn.

    Q:   Was it a traffic violation in your judgment?

    A:   It is. Basically the way he made his turn.

    Q:   Is that what you thought at the time?

    A: Oh, definitely at the time, that’s why I contin-
    ued to follow him. And then once I made the turn
    and I observed how far he had gotten from me, the
    distance that he had gained, he wasn’t going the
    speed limit. I had, you know, no way to tell exactly
    how fast, but he wasn’t going the speed limit
    because I had to accelerate excessively to try to
    catch up with him.

   The magistrate judge sought to clarify the distances (and,
by inference, the speeds) involved, asking if Officer Boehmer
could see Willis after he turned onto Charleston from Las
Vegas Boulevard, and then again after he turned onto Third
from Charleston:

    Q: So you saw him make a right turn on Third
    [from Charleston]?
16568              UNITED STATES v. WILLIS
    A:   Yes I did.

    Q: And then when you reached Third and made a
    right turn, do you recall where he was when you
    were able to see down Third Street?

    A: Yes. I believe he was already past Coolidge
    because I was saying — I remember saying to
    myself, man, this guy is driving so fa[s]t, you know
    it was almost to the point I was going to call out the
    vehicle pursuit, but I had no other description
    besides the white vehicle.

  The distance between Charleston and Third is a block and
a half. Coolidge comes into Third at an angle, joining Third
half a block up from Charleston. The magistrate judge contin-
ued:

    Q: And then when you turned north on Third
    Street, he was already halfway between Coolidge
    and Hoover?

    A:   Yes.

    Q: He must have been slowing down as he
    approached Hoover, correct?

    A:   He did.

    Q:   And he then made a right turn on Hoover?

    A:   Yes.

    Q:   Just around the corner practically —

    A:   Yes.

    Q:   — and parked —
                    UNITED STATES v. WILLIS               16569
    A:   Yes.

    Q:   On the south side of the street?

    A:   Yes, Your Honor.

When Willis parked his car, he was less than two blocks from
where he had been when Officer Boehmer had first spotted
him. He was now back on Hoover, pointed in the same direc-
tion he had been driving when he made his “rapid turn” from
Hoover onto Las Vegas Boulevard.

   Officer Boehmer never testified as to the speed limit on the
streets on which Willis traveled, or as to the exact speed Wil-
lis was traveling. He also made no attempt to explain how
Willis had been able to exceed the speed limit when he never
traveled more than two blocks in a straight line. Nor did Offi-
cer Boehmer attempt to reconcile his belief that Willis was
trying to evade him with the fact that Willis had essentially
driven in a four-and-a-half to five-block circle, coming back
onto Hoover and then stopping voluntarily.

                   3.   U-Turn on Hoover

  After parking his car on Hoover, Willis got out, “sprinted”
(Officer Boehmer’s word) across the street to a nearby apart-
ment, and banged on the door. He was admitted to the apart-
ment and stayed for a short time. He then came out of the
apartment, got into his car, and made a U-turn on Hoover. He
crossed Third Street and stopped the car at the curb on Hoo-
ver in front of what we now know was his own apartment.

  Officer Boehmer testified that Willis’s U-turn on Hoover
was illegal, but he cited no provision of any applicable traffic
law. Nevada’s traffic laws provide that “[a] U-turn may be
made on any road where the turn can be made with safety,
except as prohibited by this section and by the provisions of
N.R.S. 484.309 [driving on a divided highway] and 484.339
16570               UNITED STATES v. WILLIS
[turning on a curve or crest/grade].” Nev. Rev. Stat.
484.337(1) (2002). U-turns may not be performed at stop-
lights that have signs prohibiting these turns. Id. at
484.337(2). Nor may they be performed in a business district
unless at an intersection. Id. at 484.337(3). Las Vegas’s
municipal traffic code provides, “The driver of any vehicle
shall not turn such vehicle so as to proceed in the opposite
direction upon any street in a business district and shall not
upon any other street so turn a vehicle unless such movement
can be made in safety and without interfering with other traf-
fic.” Las Vegas Mun. Code 11.12.050 (2005).

   Nowhere in his testimony did Officer Boehmer state that
Hoover Avenue at Third Street is in a business district. We
know from Officer Boehmer’s testimony that there were resi-
dential apartments along Hoover at the point where Willis
made his U-turn. Further, Officer Boehmer’s testimony indi-
cates that there was no traffic on Hoover when Willis per-
formed the U-turn. Finally, there is nothing in Officer
Boehmer’s testimony to indicate that there was a stoplight or
a sign prohibiting a U-turn, or that Willis’s U-turn was unsafe.

                     4.   Other Evidence

   Officer Boehmer testified at the suppression hearing that he
had no recollection of having mentioned any traffic violations
to Willis during the course of the arrest, and that no traffic
citation was ever issued to Willis. Officer Boehmer further
testified that he did not mention Willis’s rapid accelerating
and speeding in either of his two written reports prepared after
the arrest. Officer Boehmer did mention Willis’s U-turn in his
reports, but only as part of the narrative leading up to Willis’s
voluntary stop in front of his own apartment. Officer Boehmer
did not indicate anywhere in his two written reports that Wil-
lis’s U-turn was illegal. Indeed, there is nothing in either of
Officer Boehmer’s two reports to indicate that Willis had vio-
lated the traffic laws in any manner, or that Officer Boehmer
had stopped Willis for a traffic violation.
                    UNITED STATES v. WILLIS                16571
          B.   Circumstances of the “Traffic Stop”

   Officer Boehmer’s testimony makes clear that he suspected
that Willis was engaged in, or had engaged in, criminal activ-
ity. He testified that his suspicions were first aroused by Wil-
lis’s manner of driving between the time of his initial turn
from, and subsequent return to, Hoover Avenue. His suspi-
cions were further aroused when Willis parked on Hoover,
left his windows rolled down, ran across the street, and
banged on the door of an apartment. At that point, Officer
Boehmer asked that a check be run on the Colorado license
plates of Willis’s car. He also asked for back-up: “Due to the
suspicious situation, the known gang, prostitution and drug
activity in the area, I just, for officer safety, I wanted another
officer there, and the time of night.” While he waited for his
back-up to arrive, Officer Boehmer made a U-turn on Hoover
and drove a little over half a block away to the west. He
parked in an alley that intersected Hoover between Third
Street and Casino Center Boulevard. He testified that he had
an unobstructed view from the alley to the apartment complex
to which Willis had run.

   Officer Boehmer testified that the license plate check
revealed that Willis’s car was listed as a “suspicious vehicle
in an earlier event almost a week earlier.” It also revealed
“that the vehicle has a missing persons [National Crime and
Information Center (“NCIC”)] hit on it.” About a week ear-
lier, the woman who owned the car Willis was driving had
been driving with Willis in Las Vegas. They were stopped by
Las Vegas police because the car had a missing person listing
on the NCIC system. During the stop, Las Vegas police offi-
cers learned that the woman was in Las Vegas on her own
volition and wanted no assistance. According to Officer Boe-
hmer, the suspicious vehicle report had been entered into the
local Las Vegas police department system at about the time
of this stop.

  Las Vegas police contacted the woman’s family and the
Escondido, California Police Department (the source of the
16572               UNITED STATES v. WILLIS
missing person listing) to tell them what they had learned.
The Escondido Police Department requested that the Las
Vegas Police Department let them know where the woman
was so that she could be removed from the missing persons
list. The record does not indicate when or if the Las Vegas
Police Department responded to this request. However, none
of this was known to Officer Boehmer as he watched from the
alley. The only thing he knew was that the car was listed as
a “suspicious vehicle” on the local Las Vegas system, and
there was an NCIC missing persons “hit” on the car.

   Officer Miller arrived in a separate police car in response
to the back-up request. While Officer Boehmer was describ-
ing the situation to Officer Miller, Willis came back out of the
apartment. Willis got into his car, made a U-turn on Hoover,
and drove less than a block. Still on Hoover, Willis pulled
over to the curb of his own accord and parked in front of his
own apartment. Officers Boehmer and Miller immediately
moved to box in Willis’s car. Officer Boehmer made a U-turn,
turned on his overhead lights, and drove up behind Willis’s
car. Officer Miller made a U-turn from the other direction,
turned on his overhead lights, and drove up to the front of
Willis’s car.

   Officer Boehmer testified that Willis opened his car door as
he was in the middle of his U-turn. Then, “as he stepped out
[of his car] I was putting my vehicle into park and I observed
a black male start looking from side to side rapidly.” Boehmer
testified, “I immediately began ordering commands to him to
step to the front of my vehicle, and also to take his hands out
of his pockets because at the time he had his hands in his
jacket pockets. . . . [F]rom my experience again, someone
that, you know, immediately opens up their vehicle and jumps
out and begins looking from side to side frantically is, in my
experience they’ve always taken off running. So before, you
know, he had a chance to, I just started giving commands.”

  Officer Boehmer testified that Willis complied with his
commands. After Willis had walked to the front of the police
                    UNITED STATES v. WILLIS                16573
car, Officer Boehmer asked him, “[D]o you have anything on
you I should know about?” According to Officer Boehmer,
Willis “said he had a gun.” Officer Boehmer says he “then
asked him to place his hands behind his back and spread his
feet apart[.]” Officer Boehmer testified that Officer Miller
“gained [Willis’s] consent” to look in his pockets, where he
found a loaded firearm. Officer Boehmer testified that he then
gave Willis a Miranda warning and asked him more ques-
tions. He testified that he asked a records clerk to run a crimi-
nal history check, and that the check revealed that Willis was
a convicted felon. Officer Boehmer placed Willis under arrest
“[f]or ex-felon in possession of a firearm, carrying a con-
cealed weapon, ex-felon failure to register at that time.” After
arresting Willis, Officer Boehmer transported him to the
Clark County Detention Center.

                        II.   Discussion

   In Whren v. United States, the Supreme Court held that the
police may make an ordinary “traffic stop” whenever they
have sufficient reason to believe that a traffic law has been
violated. It does not matter under Whren that the police might
have some ulterior motive for making the stop, so long as they
have sufficient reason based on suspicion that the traffic laws
have been violated. The Court in Whren spoke of “probable
cause,” 517 U.S. at 819, but we, along with other circuits,
have construed Whren to require only that the police have
“reasonable suspicion” to believe that a traffic law has been
broken. United States v. Lopez-Soto, 205 F.3d 1101, 1104 (9th
Cir. 2000).

   Whren gives the police considerable leeway in making traf-
fic stops, but it does not provide them carte blanche. There are
two independent requirements for a valid traffic stop under
Whren.

   First, “specific, articulable facts” to justify reasonable sus-
picion must be provided by the police officer. As stated by the
16574               UNITED STATES v. WILLIS
Supreme Court in Terry, “the police officer must be able to
point to specific, articulable facts which, together with ratio-
nal interferences from those facts, reasonably warrant [the]
intrusion.” Terry, 392 U.S. at 21 (emphasis added). See also
United States v. Michael R., 90 F.3d 340, 346 (9th Cir. 1996)
(police officer making a traffic stop must have “specific,
articulable facts which, taken together with objective and rea-
sonable inferences, form the basis for suspecting that the par-
ticular person detained is engaged in criminal activity”
(quoting United States v. Garcia-Comacho, 53 F.3d 244, 246
(9th Cir. 1995)); Lopez-Soto, 205 F.3d at 1104 (same). A
police officer may rely on his training and experience in
drawing inferences from the facts he observes, but those infer-
ences must also “be grounded in objective facts and be capa-
ble of rational explanation.” Michael R., 90 F.3d at 346.

   Second, the stop must be an ordinary traffic stop. The
Supreme Court was careful in Whren to specify that its ratio-
nale, and its holding, was limited to what it called the “run-of-
the-mine case.” Whren, 517 U.S. at 819. That is, if a detention
of a vehicle by police is other than a “run-of-the-mine” traffic
stop, Whren does not apply

   If either of these two requirements is not satisfied, a deten-
tion is not a valid traffic stop under Whren. I consider them
in sequence.

              A.   “Specific, Articulable Facts”

   A defendant has the ultimate burden of proof on a Fourth
Amendment motion to suppress. United States v. Cayman,
404 F.3d 1196, 1999 (9th Cir. 2005). But when a traffic stop
based on Whren is at issue, the police officer has the initial
burden of production. That is, Officer Boehmer had the bur-
den of providing “specific, articulable facts” to justify a “rea-
sonable suspicion” to believe that Willis had violated the
traffic laws. Terry, 392 U.S. at 21; Michael R., 90 F.3d at 346;
Lopez-Soto, 205 F.3d at 1104. In the absence of such “spe-
                    UNITED STATES v. WILLIS                16575
cific, articulable facts” provided by the police officer, the
defendant has no obligation to refute the police officer’s testi-
mony, for he has failed to satisfy his initial burden of produc-
tion. Unless the police officer provides “specific, articulable
facts,” a traffic stop under Whren is invalid.

   Officer Boehmer failed to carry his initial burden of pro-
duction of providing “specific, articulable facts” to justify a
reasonable suspicion that Willis violated the traffic laws.
Even when invited to do so, Officer Boehmer failed to point
to a single provision of Nevada or Las Vegas traffic laws that
Willis might have violated. Officer Boehmer admitted forth-
rightly in his testimony, “I don’t really write too many tick-
ets.” Rather, “I just mostly do criminal investigations.”

   Officer Boehmer first asserted that Willis’s “rapid turn”
onto Las Vegas Boulevard was a traffic violation, but he was
unable, even when asked, to specify any law that had been
violated. Officer Boehmer next asserted that Willis had bro-
ken the speed limit, but Officer Boehmer did not specify the
applicable speed limit, and was unable to say, even when
asked, exactly how fast Willis was going. It is apparent from
Officer Boehmer’s narrative that Willis’s speed would have
been limited by the route he took, for Willis never had more
than two blocks of straight driving before turning onto
another street. Finally, Officer Boehmer asserted that Willis
had made an illegal U-turn on Hoover Avenue. But it is
apparent from Officer Boehmer’s testimony that the U-turn
was accomplished on a stretch of Hoover that was bordered
by residential apartments. Officer Boehmer failed to specify
any traffic law forbidding a U-turn in a residential area. He
also failed to specify that Willis’s U-turn was performed in an
unsafe manner, or in any other manner that would have vio-
lated the traffic laws.

                      B.   “Traffic Stop”

  The totality of circumstances surrounding Officer Boehmer
and Miller’s arrest of Willis make it clear that they did not
16576               UNITED STATES v. WILLIS
perform a “run-of-the-mine” traffic stop within the meaning
of Whren. I recognize that there are circumstances in which
a valid traffic stop under Whren can take place after a car has
already been stopped. For example, if a police vehicle openly
pursues a fleeing car and the driver belatedly decides to pull
over and stop to wait for the police vehicle to catch up, no one
would dispute that the car had been subjected to a traffic stop
within the meaning of Whren. But this is hardly such a case.

   Officer Boehmer made clear in his testimony that he sus-
pected Willis of criminal activity. After Willis made his first
stop on Hoover, Officer Boehmer called for backup and drove
to a secluded alley where he could watch and wait for his
back-up. After Officer Miller arrived, Officer Boehmer told
him what was happening. Willis then returned to his car,
made a U-turn on Hoover, and drove less than a block to park
in front of his own apartment.

   After Willis had already parked his car on his own accord,
Officers Boehmer and Miller “swooped in,” boxing in the
already stopped car from the front and rear. Officers Boehmer
and Miller then behaved exactly as one would expect well-
trained officers to behave when stopping someone suspected
of criminal activity. To dissuade Willis from running away,
Officer Boehmer “immediately began ordering commands to
him to step to the front of my vehicle, and also to take his
hands out of his jacket pockets[.]” To ensure the officers’
safety, Officer Boehmer asked Willis if he had “anything on
[him] I should know about.” When Willis replied that he had
a gun, Officer Boehmer arrested him and took him to the
detention center.

  After stopping Willis, Officer Boehmer never mentioned
any traffic violation or issued any traffic citation. Nor did
Officer Boehmer ever mention any traffic violation in his two
written reports prepared after Willis’s arrest. The first time a
purported traffic violation was mentioned was when Officer
                    UNITED STATES v. WILLIS               16577
Boehmer was questioned by government counsel at the sup-
pression hearing.

                          C.   Summary

  The majority’s rationale under Whren thus fails on both
counts, either one of which is fatal. Officer Boehmer did not
provide “specific, articulable facts” that justified reasonable
suspicion that Willis had violated any traffic law. Further,
Officers Boehmer and Miller’s detention and arrest of Willis
was not a “run-of-the-mine” traffic stop within the meaning
of Whren.

                   III.   Failure to Remand

   Even if I agreed with the majority’s legal analysis, I could
not agree with its disposition. Rather than remand for fact-
finding, the majority simply affirms the denial of Willis’s sup-
pression motion.

   Because the district court concluded — as I do — that Offi-
cers Boehmer and Miller did not perform a traffic stop within
the meaning of Whren, it did not determine whether Officer
Boehmer’s testimony about Willis’s driving was credible. The
magistrate judge noted that Willis had contended that Officer
Boehmer’s testimony was “simply not credible.” But the mag-
istrate judge wrote that he did not “need [to] assess the credi-
bility of the officer’s testimony about Willis’s driving”
because there had been no traffic stop under Whren.

   Unlike the district court, the majority concludes that there
was a traffic stop under Whren. It also concludes that the traf-
fic stop was justified by a reasonable suspicion that Willis had
committed a traffic violation. In order to reach the second
conclusion, it treats Officer Boehmer’s testimony about Wil-
lis’s driving as credible. It does so despite Willis’s explicit
challenge to its credibility, and despite the magistrate judge’s
16578               UNITED STATES v. WILLIS
explicit refusal to “assess [its] credibility.” Under the circum-
stances, I would remand to the district court for factfinding.

                          Conclusion

   The majority distorts the law to hold that Officers Boehmer
and Miller performed a permissible traffic stop under Whren.
The majority recognizes the weakness of the other two ratio-
nales offered by the government — a reasonable suspicion of
criminal activity under Terry and the community caretaking
function under Cady v. Dombrowski. But the majority’s alter-
native rationale is even worse. If, on these assumed facts,
Officer Boehmer provided “specific, articulable facts” to sup-
port a reasonable suspicion that Willis had broken the traffic
laws, “reasonable suspicion” has lost much of its meaning.
And if, on these facts, Officers Boehmer and Miller per-
formed a “run-of-the-mine” “traffic stop,” those terms, too,
have lost their meaning.
