**PUBLISHED**
UNITED STATES COURT OF APPEALS FOR THE FOURTH CIRCUIT

**No. 14**  **- 4736** 

UNITED STATES OF AMERICA , Plaintiff

– Appellee ,

v.
MICHAEL JEROME PALMER , Defendant

– Appellant

.

Appeal from the United States District Court for the Eastern District of Virginia , at Norfolk

. Robert G. Doumar , Senior District Judge. ( 2:14

- cr - 00031

- RGD

- DEM

- 1 )

Argued : December 10 , 2015 Decided: April 21, 2016

Before WILKINSON , KING , and WYNN , Circuit Judges

.

Affirmed by published opinion

. Judge King wrote the opinion, in which Judge Wilkinson and Judge Wynn joined . Judge Wynn wrote a separate concurring opinion.

**ARGUED** : James Orlando Broccoletti, ZOBY, BROCCOLETTI & NORMILE, PC, Norfolk, Virginia, for Appellant. Christopher John Cati zone, OFFICE OF THE UNITED STATES ATTORNEY, Alexandria, Virginia, for Appellee. **ON BRIEF** : Dana J. Boente, United States Attorney, Alexandria, Virginia, Darryl J. Mitchell, Assistant United States Attorney, OFFICE OF THE UNITED STATES ATTORNEY, Norfolk, Vi rginia, for Appellee.2 KING, Circuit Judge: Michael Jerome Palmer appeals the district court’s denial
of his motion to suppress drug and firearm evidence seized by police officers during a traffic stop in Chesapeake, Virginia

. The court conducted an evidentiary hearing and , in early May 2014, rendered its ruling in favor of the government

. As explained below, we are satisfied that the officers did not
contravene the Fourth Amendment and thus affirm.

I.
A.
I n April 2014 , the federal grand jury in Norfolk, Virginia,
indicte d Palmer on two offenses : possessi on with intent to distribute crack cocaine, in contravention of 21 U.S.C.
§ 841(a)(1) ; and being a felon in possession of a firearm, in violation of 18 U.S.C. § 922(g)(1). Palmer moved to suppress
the drug and firearm evidence underlying the charges , which Chesapeake officers had seized during the October 2013 traffic stop of a vehicle driven by Palmer

. In May 2014, the district
court denied Palmer’s suppression motion. See United States v.
Palmer , No. 2:14

- cr - 00031 (E.D. Va. May 5, 2014), ECF No. 35 (the “Opinion”). In June 2014, Palmer pleaded guilty to both

o ffenses in the indictment , but reserv ed the right to appeal the

s uppression ruling

. I n September 2014, the cou rt sentenc ed him3 to sixty

- one months in prison

. Palmer timely not ed this appeal, and we possess jurisdiction pursuant to 28 U.S.C. § 1291.
B.
1. Because the district court denied Palmer’s motion to suppress, we recount the facts in the light most favorable to the government. See United States v. Watson , 703 F.3d 684, 689 (4th Cir. 2013). On October 15, 2013, Officer Ring of the Chesapeake police was patrolling that city’s Ipswich neighborhood. During his patrol , Ring stopped Palmer, who was driving a silver Nissan Altima , on Paramont Avenue
. When Ring exited his patrol car and gr eet ed Palmer through the driver

- side
window of the Nissan , he smelled an overwhelming odor of air
freshener . He saw a t least five air fresheners in side the car ,

some hanging in the passenger compartment and others plugged into the air

- conditioning vents. Ring advised Palmer that he
had been stopped because the Nis san ’s windows were too darkly tinted , in violat ion of state law , and also because the inspection sticker on the vehicle’s front windshield appeared
fraudulent. Ring then obtained Palmer’s driver’s license and
the vehicle ’s registration card , and returned to his patrol car
to make a database check

. From the driver’s licen se and registration Officer Ring learned that Palmer listed a P.O. box as his address and that4 the Nissan was registered to a woman who was not present
. Within minutes of beginn ing the database check , Ring also
learned that Palmer was a suspected member of a gang called the Bounty Hunter Bloods, according to a “ caution ” notice issued by
the nearby Norfolk Police Department. See Opinion 2. Ring
advised his colleague , Officer Blount

— who was also on the

scene

— of Pa lmer’s purported gang affiliation , and asked Blount about the availability of a drug dog

. Officer Ring also sought information on Palmer from a nother
database called LInX. Ring could not initially log into the LInX system because his former partner had changed the password.

He eventually accessed LInX , however

— about seven minutes into
the traffic sto p

— by u tilizing Officer Blount’s login
credentials

. As Ring was logging into LInX and searching its
database , he called about a drug dog

. Ring relayed by radio the information that he had gathered : Palmer was nervous; there was an overwhelming odor of air freshener from the Nissan ; there were at least five air fresheners in the car ; Palmer’s driver’s license address was a P.O. b ox , as opposed to a street address ; the Nissan was registered to someone other than the driver ; and
Palmer was a suspected member of the Bounty Hunter Bloods

. About eleven minutes into the traffic stop, Officer Ring
id entified Palmer in LInX. Ring lear n ed that Palmer had a criminal record that included f our arrests on drug charges plus5 a n arrest for illegal possessi on of a firearm b y a convicted
felon

. As a result, Ring radioed again about a drug dog , but was unable to confirm its availability

. After complet ing his

L InX search , Ring returned to the Nissan from his patrol car

. Because he suspected the inspection sticker was f raudulent , Ring
decided to verify the sticker’s authenticity by looking at the
back of it , which w ould enable him to determine whether it w as legitimate

. After asking Palmer to exit the Nissan , Ring leaned through the open driver

- side door and examined the back of the inspecti o n sticker

. While reading the sticker

— which he
concluded was legitimate

— Ring smelled marijuana

. Officer Ring immediately advised Palmer that he had grounds
to search the Nissan

. Because Ring wanted to be “110% sure” that the Nissan contained drugs before searching the vehicle, however, he again checked on the drug dog’s availability

. See Opinion 3. A t that point

— a pproximately seventeen minutes
after the traffic stop had been initiated

— Ring called Officer Duncan, who had a drug dog

. About t en minutes later, Duncan arrived with the drug dog Boomer
. Duncan walked Boomer around the Nissan , and the dog alerted twice.
O fficers Ring and Duncan the reafter entered and searched
the Nissan . They discovered a clear plastic bag containing
crack cocaine in the center front console and a 40

- caliber Smith
& Wesson pistol wedged between the driver’s seat and th e6 console. As a result, Palmer was arrested. After the search
and arrest , Ring measured the Nissan’s window tint

. Th o se measurements confirmed Ring’s initial suspicion that the Nissan’s windows were illegally tinted. 1
2

. On April 29, 2014, the district court conducted an evidentiary hearing on Palmer’s suppression motion

. During the hearing , Officer Ring

— the prosecution’s only witness

— recounted his actions and observations during the traffic stop

. Officer Ring explained that, before the traffic stop, he
knew of numerous citizen complaints to the authorities about the
sale a nd use of illegal drug s in the Ip swich area . He also described his familiari ty with Virginia ’s legal limits on window tinting and said that he “could barely see into the vehicle ” that Palmer was driving. See J.A. 71

- 7 4

. 2 Aside from the window tint, Ring suspected that the Nissan’ s inspection sticker was illegal , based on his experience and having stopp ed numerous vehicles with fraudulent stickers . Ring explained that he could

1 Officer Ring found that the side

- front and side

- rear windows of the Nissan violated Virginia law by allow ing light transmittance of only 40 % and 25 %, respectively. Virginia requires side

- front windows to permit light transmittance of at least 50 % , and s ide

- rear windows to permit light transmittance of at least 35 %

. See Va. Code Ann. § 46.2

- 1052(C).

2 Citations herein to “J.A. __” refer to the contents of the Joint Appendix filed by the parties in this appeal.7 not see the perforated portion that sh ould be observable on a legitimate sticker

. The back of a legitimate inspection sticker, he said , shows the perforated portion and contains information identifying the vehicle. Although it is understandable for any person to be nervous when interacting with the police, Officer Ring said that Palmer “appeared to be more nervous than normal ” during the traffic
st op. See J.A. 79. Specifically, Ring observed that Palmer was “being overly cooperative but still very nervous in his
demeanor.” Id. Regarding Palmer’s liberal use of air
fresheners , Ring explained that drug traffickers often use “heavy air freshening” to mask the “pungent odor” of marijuana.
See i d. at 80. Ring also explained that drug traffick ers often operat e vehicle s registered to other s . That is so because, when the police apprehend a drug traffi cker , the y tend not to seize
the vehicle if it is registered to someone not present. Similarly, w hen Ring was asked

— in light of the thousand

- plus drug investigations in which he had participated

— whether a P.O. box on a driver’s license can be indicative of involvement in drug trafficking, he responded affirmatively. Officer Ring also e mphasized that he developed a concern for officer safety after learning of Palmer’s suspected gang affiliation a nd prior criminal record. Ring stated that “[c]riminal stre et gangs are known for violence ” and that his8 department ha d received “ intelligence reports of threats against law enforcement specifically from the Blood gang.” See J.A. 86. Ring explained that Palmer’s history of multiple drug arrests,
as well as his arrest for possessing a firearm as a convicted felon, caused Ring to believe Palmer “ would potentially still
have a firearm on him

. ” Id. According to Officer Ring , Palmer was initially hesit ant to get out of the Nissan , and Palmer had th ereafter lingered near
the vehicle’s front door until Ring requested that he move to
the car ’s rear
. S hortly thereafter, w hile Ring was inside the passenger compartment check ing the inspection sticker , he “smell[ed] the marijuana very faintly” before his “sense of smell [was] overwhelmed with the air freshener.” See J.A. 90. Ring confirmed that Officer Blount smell ed marijuana as well. Officer Ring made at least two other observations that strengthened his suspicion of criminal activity . First, Palmer “had two cell phones on his hip.” See J.A. 93. According to Ring , “[i]t’s common for people who distribute narcotics to have more than one cell phone in their possession.” Id. He said
that tho s e involved in drug trafficking often rely on one phone
to store contacts and pictures while utilizing the other phone to arrange drug deal s . Second, Ring believed that Palmer was seeking to divert suspicion from himself as they waited for Officer Duncan an d the drug dog . Palmer “kept telling us that9 he helps the police and that he ha [d] a contact [in] the police department. ” See i d. at 95.
A s the hearing ended , the district court remarked that Officer Ring had “presented to this Court a very, very careful appearance, one of a person who is very seriously trying to abide by what the requirement s of the law are.” See J.A. 210. Although it was inclined to believe that Ring had acted lawfully, the court took the suppression motion under advisement

. C
. On May 5, 2014, w ithin a week of the evidentiary hearing,
t he district court fil ed its Opinion denying the suppression
motion

. 3 T he Opinion concluded that Officer Ring had properly stopped the Nissan , based on suspicion s of a window tint
violation and a fraudulent inspection sticker. The Opinion explained that Ring also possessed the reasonable, articulable suspicion of criminal activity necessary to extend the traffic stop , identifying eight supporting factors in that regard :

3 Officer Ring made a video recording of the traffic stop from a camera he was w ea r ing on his uniform

. After viewing the video during the evidentiary hearing as Ring testified, the district court observed that Ring presented “a very truthful appearance.” See J.A. 206. The court later revie wed the video “at a slow pace in chambers, stopping to analyze the footage from time to time to be doubly sure of its interpretation.” See Opinion 1.10 • Palmer was in a high crime area where citizens were complaining about drug dealing ;

• Ring believed that the Nissan’s windows were illegally tinted;

• Palmer was nervous;

• T he Nissan emitted a n “overwhelming” scent of air freshener from the multiple air fresheners;

• Palmer was a suspected member of a violent gang called the Bounty Hunter Blood s ; 4

• Palmer’s driver’s license listed a P.O. b ox address , rather than a residence;

• Palmer was driving a vehicle registered in another person ’s name; an d

• Palmer had “ a criminal record that included four previous arrests for narcotics charges as well as a charge of possession of a firearm by a convicted felon. ”
See Opinion 9. T he Opinion explained that those factors , “when taken together, [gave] rise to reasonable suspicion because they eliminate [d] a substantial portion of innocent travelers and
indicate [d] that criminal activity [was] afoot.” Id. That is, Ring possessed the “ reasonable suspicion necessary to extend the stop beyond its original scope and duration as soon as he

c ompleted the comput er checks. ” Id.

4 The district court observed that it was “very familiar with the Bloods an d their propensity for violence, ” based on “its prior cases involving members of th[at] gang.” See Opinion 9 n.3.11 The Opinion also explained that Officer Ring had probable cause to search the vehicle when he first smelled marijuana and also after the drug dog ale rted. Without specify ing whether Ring’s entry to check the inspection sticker constituted a
search of the Nissan , the Opinion conclude d that Ring had “reasonable suspicion .

. . to investigate the inspection sticker’s authenticity , ” and that he had dispel led that suspicion by “ the least intrus ive means in a short period of
time

. ” See Opinion 12

- 13. Ring’s d etecti on of a m arijuana odor while in the car , in turn, supplied ample cause for a search of
the Nissan

. According to the Opinion, t he officers were also entitled to delay searching the vehicle and wait for a drug dog

. 5
In sum, t he Opinion rule d that Officer Ring had made a legitimate traffic stop, that he had sound reasons for extend ing the stop , and that his subsequent actions did not violate the
Fourth Amendment

. Palmer’s motion to suppress the evidence was therefore denied

. The constitutionality of Ring’s search

- and

seizure activities is the sole question preserved by Palmer’s conditional guilty plea

.

5 The Opinion reasoned in the alternative that, even if Officer Ring’s entry into the vehicle to examine the inspection sticker was somehow improper, the drug and firearm evidence could not be suppressed. That was so because “Ring’s actions demonstrate conclusively that he would have brought the [drug dog] to the [traffic] stop to perform the [dog sniff] test irrespective of his entrance into the vehicle.” See Opi nion 17.12 II. We review de novo a district court’s rulings with respect
to reasonable suspicion and probable cause

. See Ornelas v. United States , 517 U.S. 690, 699 (1996)

. Absent c lear error, we will not disturb factual findings made by a district court after an evidentiary hearing on suppression issues. See United States v. Dire , 680 F.3d 446, 473 (4th Cir. 2012). When a district
court has denied a suppression motion , we view the evidence in the light most favorable to the government. See United States
v. Watson , 703 F.3d 684, 689 (4th Cir. 2013).

II I. On appeal, Palmer contends t hat Officer Ring did not have

an y objectively reasonable basis for initiating the traffic stop
of the Nissan , and that Ring unreasonably expanded the scope o f the stop shortly after it began

. Palmer also labels Ring’s entry into the Nissan to view the inspection sticker as constitutionally impermissible. The government counters that Ring legitimately stopped Palmer for suspected traffic
violations , and that Ring’s subsequent actions were consistent with the Fourth Amendment

. A. Before assessing the parties’ contentions, we identify some pertinent legal principles. The Fourth Amendment guards against13 “ unreasonable searches and seizures

. ” See U.S. Const. amend.
IV. A traffic stop is a “seizure” within the meaning of the
Fo urth Amendment and must be reasonable under the circumstances.
See Delaware v. Prouse , 440 U.S. 648, 653

- 54 (1979). In that regard, the courts a ssess the constitutional ity of a traffic stop under the two

- prong standard articulated in Terry v. Ohio , 392 U.S. 1 (1968). See Arizona v. Johnson , 555 U.S. 323, 330

- 31 (2009). Pursuant thereto, we first assess whether the articulated bases for the traffic stop w ere legitimate. See United States v. Rusher , 966 F.2d 868, 875 (4th Cir. 1992). Second, we examine whether the actions of the authorities during
the traffic stop were “ reasonably related in scope ” to the bas e s for the seizure

. I d. (internal quotation marks omitted).
1. As the Supreme Court has explained , Terry ’s first prong is satisfied “ whenever it is lawful for police to detain an automobile and its occupants pending inquiry into a vehicular
violation.” See Johnson , 555 U.S. at 327. Without question, such a violation may include failure t o comply with traffic
laws. See, e.g. , United S tates v. Green , 740 F.3d 275, 279 n.1 (4th Cir. 2014) ( concluding that windows “illegally tinted” under Virginia law “justif[ied] the stop”); United States v. Digiovanni , 650 F.3d 498, 506

- 07 (4th Cir. 2011) ( observing that
officer made traffic stop on basis of perceived violation of14 Maryland law that prohibits following another vehicle too closely). In assessing the legitimacy of a traffic stop , we do not attempt to discern an officer’s subjective intent for stop ping
the vehicle

. See United States v. Branch , 537 F.3d 328, 340 (4th Cir. 2008)

. We simply ask whether “the circumstan ces, viewed objectively, justif y th[e] action.” See Whren v. United
States , 517 U.S. 806, 813 (1996) (internal quotation marks omitted) ; United States v. Johnson , 734 F.3d 270, 275 (4th Cir. 2013) (observing that a traffic stop is legitimate “when officers observe a traffic violation, regardless of their true, subjective m otives for stopping the vehicle”).
2. Terry ’s second prong restrict s the range of permissible
action s that a police officer may take after initiat ing a traffic stop

. An officer is entitled to conduct safety

- related
checks that do not bear directly on the reasons for the stop,
such as requesting a driver’s license and vehicle registration, or checking for criminal records and outstanding arrest
warrants. See Rodriguez v. United States , 135 S. Ct. 1609,
161 5

- 1 6 (2015)

. Generally, however, an officer’s focus must remain on the bases for the traffic stop , in that the stop must
b e “sufficiently limited in scope and duration to satisfy the conditions of an investigative seizure.” See United States v.15 Guijon

- Ortiz , 660 F.3d 757, 764 (4th Cir. 2011) (internal quotation marks omitted)

. Thus, w he n following up on the initial reasons f or a traffic stop, the officer must employ “the least intrusive means reasonably available to verify or dispel [his] suspicion in a short period of time.” See Digiovanni , 650 F.3d at 507 ( internal quotation marks omitted )

. To be clear, the law does
not require that the officer employ the least intrusive means conceivable

. See United States v. Sharpe , 470 U.S. 675, 686

- 87 (1985) ( “ A creative judge engaged in post hoc evaluation of police conduct can almost always imagine some alternative means by which t he objectives of the police might have been accomplished.” )

. If an officer act s unreasonably in attempting to confirm his suspicions during a traffic stop , however, he
runs afoul of Terry ’s second prong. Relatedly , a legitimate traffic stop may “become unlawful if it is prolonged beyond the time reasonably required” to complete its initial objective s . See Illinois v. Caballes , 543
U.S. 405, 407 (2005). Put differently, an officer cannot investigate “a matter outside the scope of the initial stop”
unles s he receives the motorist’s consent or develops reasonable, articulable suspicion of ongoing criminal activity.
See Digiovanni , 650 F.3d at 507.16 Reasonable suspicion is a “commonsense, nontechnical”
standard that relies on the judgment of experienced la w enforcement officers , “not legal technicians.” See Ornelas v. United States , 517 U.S. 690, 695 (1996) (in ternal quotation marks omitted). As we recently explained i n United States v.
Williams , t he articulated factors support ing reasonable suspicion during a traffic stop “ must in their totality serve to eliminate a substantial portion of innocent trave lers , ” and also demonstrate a connection to criminal activity. See 808 F.3d 238, 246 (4th Cir. 2015) (internal quotation marks omitted). Finally, alt hough an officer may extend a traffic stop when he possesses reasonable suspicion, he cannot search the stopped vehicle unless he obtains consent, secures a warrant, or develop s probable cause to believe the vehicle contains evidence of criminal activity. See United States v. Baker , 719 F.3d 313, 319 (4th Cir. 2013). An officer’s detection of marijuana odor is sufficient to establish such probable cause, see United
States v. Carter , 300 F.3d 415, 422 (4th Cir. 2002), as is a trained drug dog’s alert on th e vehicle, s ee United States v. Kelly , 592 F.3d 586, 592 (4th Cir. 2010). With the foregoing principles in mind, we t urn to the issues presented in Palmer’s appeal.17 B.
1.

W ith respect to Terry ’s first prong

— whether Officer Ring’s articulated bases for the traffic stop were legitimate

— Palmer assert s that Ring lacked an y objectively reasonable grounds for stopping the Nissan

. That contention is meritless. Ring was familiar with the limits on window tint under Virginia
law and, in his view , the Nissan’s windows were too dark. Palmer points to nothing that indicates the district court clearly erred in crediting Ring’s testimony on that issue. See United States v. McGee , 736 F.3d 263, 271 (4th Cir. 2013) (concluding that district court’s relianc e on officer ’s testimony regarding inoperative brake light was not clearly erroneous). A s we have recognized , illegally tinted windows are alone “ sufficient to justify ” a traffic stop
. See Green , 740
F.3d at 279 n.1. We thus reject Palmer’s contention that Ring
lacked an y objectively reasonable basis for stopping the Nissan

. 2. Turning to the events that transpired after the Nissan had been stopped, Palmer acknowledges that when an officer has probable cause to believe a vehicle contains co ntraband, the Fourth Amendment “permits police to search the vehicle without
more.” See Br. of Appellant 31 (internal quotation marks omitted). While checking the Nissan’s inspection sticker,18 Officer Ring smelled marijuana. At that point, he had probabl e cause to believe the vehicle contained contraband, and was
th erefore entitled to search it. See Carter , 300 F.3d at 422. Thus, unless Palmer can demonstrate some constitutional violation between the time the stop began and the point that Ring smelled m arijuana , the evidence cannot be suppressed. 6 In that regard, Palmer asserts that Ring transgressed Terry ’s second prong b y taking actions during the traffic stop that were
not reasonably related in scope to the initial bases for the stop
.

a. According to Palmer, Officer Ring unreasonably expanded the scope of the stop by beginning an unjustified drug investigation. The government contends, however, that Ring’s actions were supported by reasonable suspicion.

A m otorist stopped by the police is obliged to endure “certain negligibly burdensome precautions” that may not relate directly to the reason for the traffic stop , such as checking
whether the driver has a criminal record or outstanding
warrants
. See Rodriguez , 135 S. Ct. at 1616 ; see also Muehler

6 Rather than search immediately after smelling marijuana, Officer Ring waited about ten minutes for the drug dog Boomer to arrive . The dog’s alerts provided strong additional support for the proposition that the Nissan contained contraband. Se e Kelly , 592 F.3d at 592.19 v. Mena , 544 U.S. 93, 101 (2005) (concluding that questioning unrelated to basis for traffic stop was not unlawful because it did not extend detention)

. T hose routine checks reflect the reality that traffic stops are “especially fraught with danger to pol ice officers ,” and further the strong interest in allowing
an officer to complete his traffic mission safely

. See Michigan v. Long , 463 U.S. 1032, 1047 (1983)

. Indeed, i n Terry itself, the Supreme Court

— describing “[t]he crux of th[e] case”

— emphasize d the “immediate interest of the police officer in taking steps to assure himself that the person with whom he is dealing is not armed with a weapon that could unexpectedly and fatally be used against him.” See 392 U.S. at 23. Palmer suggests that it was unreasonable for Officer Ring

— after learning of the “gang alert” indicating that Palmer was
associated with the Bounty Hunter Bloods

— “to delve into [ his ] prior criminal record , ” because it had “ absolutely nothing to do with investigating a window tint or inspection sticker
violation.” See Br. of Appellant 18. To describe th at contention is to discard it. A police o fficer is entitled to inquire into a motorist’s criminal record after initiating a traffic stop , and we cannot fault Ring

— faced with a suspected member of a violent gang

— for doing so here. See Green , 740 F.3d at 281 ( observing that “concern for officer safety” justified “criminal history check” )

. In short, Ring’s brief20 investigation into Palmer’s criminal record fell squarely within the range of actions permitted under Terry ’s second prong

. Nor did Officer Ring’s detention of Palmer prior to smelling marijuana unreasonably expand the scope or duration of
the traffic stop
. We are satisfied that, a fter accessing
Palmer’s criminal record in LInX , Rin g possessed a reasonable, articulable suspicion that Palmer was engaged in criminal activity. In other words, the information on which Ring relied
eliminate d a substantial portion of innocent travelers and
lo gically demonstrated a connection to unlawful conduct. T he Opinion identified eight factors in that regard : Palmer was in a high crime area where citizens were complaining about drug dealing ; Ring believed that the Nissan’s windows were illegally tinted; Palmer was nervous; t he Nissan emitted a n “overwhelming”
scent of air freshener from multiple air fresheners; Palmer was

a suspected member of the Bounty Hunter Bloods ; Palmer’s driver’s license listed a P.O. box address, rather than a
residence; Palmer w as driving a vehicle registered in another person’s name; and P almer had “a criminal record that included four previous arrests for narcotics charges as well as a char ge of possession of a firearm by a convicted felon.” See Opinion
9.
Palmer insists that most of those factors “ relate [] to perfectly innocent behavior and are not indicative of criminal21 activity.” See Br. of Appellant 19. He fails to appreciate , however, that reasonable suspicion is based on the totality of the circumstances, and may well “ exist even if each fact standing alone is susceptible to an innocent explanation.” See United States v. McCoy , 513 F.3d 405, 413

- 14 (4th Cir. 2008) (footnote omitted). Resolving the reasonable

- suspicion question turns on whether the articulated fa ctors , taken together, show ed a connection to ongoing criminal activity. Palmer maintain s that
the various factors evince Officer Ring’s “attempt to take a series of perfectly mundane, innocent, and easily explained behaviors and circumstances and weave them i nto a web of deception.” See Br. of Appellant 24 (internal quotation marks omitted). The government cou n t ers that Ring described how th ose factors were connected to suspected criminal conduct

. As we have recognized with respect to a reasonable

suspicion inquiry, “it is entirely ap propriate for courts to
credit the practical experience of officers who observe on a daily basis what transpires on the street. ” See Branch , 537
F.3d at 336

- 37 ( internal quotation marks om itted ). We do not , however, credit that experience blindly. See Williams , 808 F.3d
at 253. Instead, we expect police officer s to articulate how that experience applies to the facts at hand

. See United States

v. Foster , 634 F.3d 243, 248 (4th Cir. 2011) (“[A]n officer and22 the Government must do more than simply label a behavior as ‘suspicious’ to make it so.”). Officer Ring knew that the Ipswich neighborhood was a high

crime area and that the police had received complaints about illegal drug activity there

. See Branch , 537 F.3d at 338 (observing that “an area’s propensity toward criminal activity is something that an officer may consider” in forming reasonable suspicion (internal quotation marks omitted))

. It is compelling that, w hen Ring approached the darkly tinted Nissan, he smelled

an overwhelming odor from the air fresheners that he could see
in the vehicle , suggesting an effort to conceal the scent of drugs

. See United States v. Foreman , 369 F.3d 776, 785 (4th Cir. 2004) ( concluding that air fresheners on rearview mirror supported reasonable suspicion because they are “ commonly used to mask the smell of narcotics ”). Significantly , Officer Ring learned , early in the traffic stop, that Palmer was a suspected member of the Bounty Hunter
Bloods

. Ring k new that the Blood s had th reatened law
enforcement during hi s serv ice as a police officer and that such
gangs a re frequently involved in organized criminal activity such as “narcotics distribution.” See J.A. 86. Ring also
ascertained that Palmer had at least four earlier arre sts on drug charges and was probably a convicted felon. Indeed, he had been charged previously as a felon in possession of a firearm

.23 As we explained in United States v. Sprinkle , “an officer can couple knowledge of prior cr iminal involvement with more concrete factors in reaching a reasonable suspicion of current
crim inal activity

. ” See 106 F.3d 613, 617 (4th Cir. 1997)

. At minimum, such “ concrete factors ” in this situation included the overwhelming odor from multiple air fresheners and Palmer’s apparent gang membership. Put succinctly, the factors identified by the Opinion

— viewed in their totality

— eliminate d a substantial portion of
innocent travelers and demonstrate d a connection to possible criminal activity. 7 We a re thus satisfied that Ring’s actions prior to examining the Nissan’s inspection sticker were entirely permissible under Terry ’s second prong, because Ring did not unreasonably expand the scope of the traffic stop

.

7 Some of the factors identified by the district court , when viewed in isolation, provide somewhat weaker support for reasonable suspicion. First, a driver’s nervousness is not a particularly good indicator of criminal activity, because most everyone is nervous when interacting with the police. See Williams , 808 F.3d at 248. Second, the listing of a P.O. box as an address on a driver’s license, as opposed to a residential address, is not a strong indicator of suspicious conduct

. See id. at 250

- 51. Finally, simply driving a vehicle registered to a n absent third party is a lso not a strong factor , but could, in the proper situation, indicate the possibility of a “ stolen vehicle or drug trafficking.” See United States v. Ludwig , 641 F.3d 1243, 1249 (10th Cir. 2011) (internal quotation marks omitted ).24 b

. Palmer also maintains that Officer Ring conducted a
warrantless search of the Nissan without probable cause when he
stuck his head inside the car to examine its inspection sticker. According to Palmer, Ring’s actions constituted “the most intrusive means of confirming or dispelling the val idity of the sticker.” See Br. of Appellant 33. The government counte rs that Ring did not conduct a search within the meaning of the
Fourth Amendment , and argues that Ring was simply seeking “a better look” at “an item that a motorist is lega lly required to display on [his] vehicle for ready inspection by law
enforcement.” See Br. of Appellee 38. i. Palmer frames his contention regarding Officer Ring’s
examination of the inspection sticker in terms of
“reasonableness.” Under the applicable principles, to contest Ring’s entry into the Nissan on the ground that it was an illegal search, Palmer must show that he had “ a legitimate expectation of privacy in the area searched

. ” See United v.
Castellanos , 716 F.3d 828, 832 (4th Cir. 2013) (relying on Rawling s v. Kentucky , 448 U.S. 98, 104

- 05 (1980))

. Palmer has not asserted, much less shown, any legitimate expectation of privacy that was unreasonably infringed

. He therefore cannot rely merely on Ring ’s examination of the inspection sticker as a25 basis for suppress ing the cocaine and firearm evidence

. See id.
at 834

- 35 ( recognizing that defendant who fails to show reasonable expectation of privacy cannot challenge warrantless search of vehicle ).
i i. Although Palmer has fail ed to establish any expectation o f privacy, he also asserts that the district court clearly erred in its findings regarding the inspection sticker ’s appearance
and , consequently, that Officer Ring lacked a reasonable suspicion that the sticker was fraudulent

. Palmer also contends
that Ring failed to utilize the least intrusive means reasonably available to investigate the sticker

. W e evaluate those contention s under Terry ’s second prong

. See Guijon

- Ortiz , 660
F.3d at 764. When reviewing factual findings for clear error, “[w]e partic ularly defer to a district court’s credibility determinations, for it is the role of the district court to observe witnesses and weigh their credibility during a pre

- trial motion to suppress.” See United States v. Abu Ali , 528 F.3d 210, 232 (4th Cir. 2008 ) (internal quotation marks omitted )

. The Opinion credited Officer Ring’s testimony regarding the appearance of the inspection sticker during the traffic stop , explicitly rel ying on Ring’s observations that he “had seen
numerous fraudulent stickers” and that the Nissan’s inspection26 sticker “looked like those fraudulent stickers he had seen in the past.” See Opinion 11. T he district court also foun d that Ring could not see , from outside the Nissan, “the perforated portion that sits in the middle of the sticker and is designed to prevent sticker theft by detaching.” Id. Moreover, t he
court itself “examined the sticker both in the video [of the traffic stop] and in a photograph” t hat Palmer introduced into
evidence. See i d. at 12. Based on Officer Ring’s testimony and the district court’s examination of the evidence, the Opinion found that the inspection sticker was lighter in color than normal and that “the perforated middle portion [was] not visible from the car’s
outside.” See Opinion 12. Palmer characterizes the evidence differently , but points to nothing that contradict s the court’s findings. In such circumstances, we cannot say that the court clearly erred. See McGee , 736 F.3d at 271

. Because Ring had a legitimate basis for believing that the inspection sticker was fraudulent, we agree that the facts recited by the court , “coupled with Officer Ring’s training and experience with inspection stickers, ” support the “ reasonable suspicion Ring required to investigate the sticker’s authenticity. ” See Opinion 12.27 i i i

. Finally, Palmer argues that , even if Officer Ring possessed a reasonable suspicion that the i nspection sticker was fraudulent, hi s means of investigation w ere improper

. Palmer posits two alternatives in that regard : Ring could have “run the number on the sticker through the State Police database” ; or he could have “asked for the inspection certificate.” See Br. of Appellant 33. In assessing th o se alternatives , w e must decide whether the district court correctly conclude d that Ring employed “the least intrusive means reasonably available to verify or dispel [his] suspicion in a short period of time.”
See Digiovanni , 650 F.3d at 507 (internal quotation marks omitted)

. The burden of demonstrating the appropriateness of Officer Ring’s conduct is on the government. See Florida v. Royer , 460
U.S. 491, 500 (1983) (plurality opinion)

. We are mindful , of

course , t hat t he “ scope of the intrusion permi tted will vary , ” depending on the specific facts and circumstances. I d. A gain ,

we are bound by the findings of the district court unless they are clearly erroneous. See Abu Ali , 528 F.3d at 232. In rejecting Palmer’s theories for less intrusive alternatives , the Opinion explained that it was not clear that Officer Ring

— a city police officer

— had access to a state police database of
vehicle registration information. T he Opinion also observed28 th at there was no indication that the inspection certifica te was in the Nissan during the traffic stop.
We cannot doubt Officer Ring’s statement that he was not familiar with any state database such as Palmer describes . Nor are we persuaded that the presence or absence of the inspection
certificat e has any significance. Ring was entitled to ask
Palmer to step out of the vehicle, see Pennsylvania v. Mimms , 434 U.S. 106, 111 (1977) (per curiam) , and it does not give us

pause

— in light of Palmer’s affiliation with a violent gang , his prior criminal charge s , and his apparent felony conviction

— that Ring would request that Palmer exit the Nissan rather than
have him reach for something out of sight in the passenger compartment. Finally, neither of Palmer’s proposals would have been more expeditious, because Ring

— in examining the back of the inspection sticker

— was promptly in and out of the Nissan. The governmen t has therefore satisfie d its burden , readily showing that Ring’s means of investigating the inspection
sticker were appropriate and not unreasonably intrusive

. In these circumstances, w e are convinced that no
constitutional violation occurred. See Sharp e , 470 U.S. at 687 (“The question is not simply whether some other alternative was available, but whether the police acted unreasonably in failing to recognize or to pursue it.”)

. As a result, the district
court correctly den ied Palmer’s suppression motion.29 IV. Pursuant to the foregoing, the judgment of the district court is affirmed.

AFFIRMED30 WYNN, Circuit Judge, concurring : I fully concur in the majority opinion. I write separately to emphasize that while the Supreme Court omitted criminal background checks from its list of “ordinary inquiries” authorized incident to every traffic stop, Rodriguez v. United
States , 135 S. Ct. 1609, 1615 (2015), this Court in United
States v. Green , 740 F.3d 275 (4th Cir. 2014) , held that a traffic stop was reasonably prolonged in order to conduct a background check because the driver’s “ demeanor and behavior throughout the traffic stop in conjunction with [ an outstanding ] protective order [against the driver] raised concerns about officer safety.” Id. at 281. In this case, the specific circumstances of the stop indicate the officer had at least some legitimate concern for
his own s afety. Thus, I agree with the majority opinion that

“ we cannot fault Ring

– faced with a suspected member of a violent gang

– for [inquiring into the mo torist’ s criminal record] here.” Ante , at 19.