266 F.3d 1 (1st Cir. 2001)
UNITED STATES OF AMERICA, Appellee,v.ROTH CHHIEN, Defendant, Appellant.
No. 00-2230
United States Court of Appeals For the First Circuit
Heard Aug. 2, 2001Decided September 24, 2001

APPEAL FROM THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF NEW HAMPSHIRE
[Hon. Paul J. Barbadoro, U.S. District Judge][Copyrighted Material Omitted]
Elizabeth L. Prevett, Federal Defender Officer, for  appellant.
William E. Morse, Assistant United States Attorney, with  whom Paul M. Gagnon, United States Attorney, and Jean B. Weld,  Assistant United States Attorney, were on brief, for appellee.
Before Boudin, Chief Judge, Selya and Lipez, Circuit Judges.
SELYA, Circuit Judge.


1
A jury convicted defendant-appellant Roth Chhien of possessing five grams or more of crack  cocaine, intending to distribute it.  See 21 U.S.C. §§  841(a)(1), 841(b)(1)(B)(iii).  The district court sentenced him  as a career offender.  Chhien now appeals, assigning error both  to the district court's denial of his pretrial motion to  suppress evidence and to its sentencing determination.  We  affirm.

I.  BACKGROUND

2
During the afternoon of August 21, 1998, the appellant  -- a twenty-nine year old native of Cambodia -- drove north on  Interstate Route 93 in Salem, New Hampshire.  He was traveling  at the speed limit when he passed a state police cruiser  stationed on the median strip.  The cruiser's sole occupant,  trooper Lawrence Holdsworth, observed two violations of state  law:  the appellant was driving perilously close to the vehicle  in front of him and his car was equipped with blue-tinted  aftermarket lights.1  Holdsworth, a member of an elite team (the  so-called Enhanced Enforcement Unit) trained to "look beyond the  traffic ticket," i.e., to attempt to ferret out serious criminal  activity while conducting routine traffic patrols, commenced  pursuit.


3
Holdsworth signaled the appellant to pull his car to  the side of the road.  He then approached the driver's side and  asked for the appellant's license and registration.  After a  computer check proved unremarkable, Holdsworth ushered the  appellant to the front of his car and inquired about the blue-tinted lights.  The appellant acknowledged having purchased  them, but claimed that he did so without any awareness of the  statutory proscription.


4
Holdsworth asked if he could conduct a pat-down search  for weapons and the appellant acquiesced.  During the frisk,  Holdsworth felt something "hard" -- a "substantial lump" -- in the  appellant's right front pants pocket.  When he inquired about  the object, the appellant responded that it was a large wad of  cash, totaling $2,000.


5
Holdsworth grew increasingly suspicious.  He began to  question the appellant about where he had been and where he was  going.  The appellant told him that he had bought some stereo  equipment in Lowell, Massachusetts, and was heading to his home  in Franklin, New Hampshire.  He asserted that he had made no  stops along the way.  The trooper then crossed over to the  passenger side of the vehicle and posed a similar set of  questions to the appellant's companion, Melanie Baker (who had  remained seated inside the car throughout the initial phase of  the highway stop).  Baker verified the trip to Lowell and the  purchase of stereo equipment.  When asked if she and the  appellant had made any other stops, she mentioned that they had  driven to the Lowell home of one of the appellant's relatives. Once there, she waited in the car while the appellant went  inside.


6
Returning to the appellant (who was still standing near  the front of the car), Holdsworth probed the discrepancy.  The  appellant immediately amended his story and confirmed that he  and Baker had stopped at the home of one of his relatives for a  brief visit.  But another discrepancy emerged:  according to the  appellant, both he and Baker had entered the dwelling.


7
Disturbed by these contradictions, Holdsworth repaired  to his cruiser and radioed for assistance.  Trooper Timothy  Stearns, another member of the Enhanced Enforcement Unit,  arrived within a minute or so.  Holdsworth was drafting a  warning.  As the troopers conversed, they noticed Baker's head  sink from view and then bob up and down.  Curious about these  awkward movements, Holdsworth directed Stearns to investigate.


8
Stearns approached the vehicle.  Baker's hands were  clenched and Stearns asked to see them.  Baker refused. Stearns, fearing that Baker had a gun, unsnapped his holster,  renewed his demand, and hollered to Holdsworth "she won't show  me her hands!"  Holdsworth sprang from the cruiser and ran to  assist.  When Stearns repeated his request, Baker finally  unclenched her fists and raised both hands.  At that point,  Holdsworth yanked her from the car.  The troopers then noticed  in plain view on the front passenger seat a small plastic bag  containing white powder.


9
The troopers immediately concluded that the white  powder was contraband.2  Arrests, Miranda warnings, see Miranda v. Arizona, 384 U.S. 436, 444-45 (1966), and further questioning  followed apace.  During this brief roadside interrogation, the  appellant admitted that the plastic bag contained crack cocaine  purchased in Lowell.  Baker confirmed this tale, adding that she  had tried to conceal the contraband when Holdsworth intervened. The troopers then transported the suspects to a nearby station  house.


10
On September 9, 1998, a federal grand jury indicted the  appellant for possession with intent to distribute five grams or  more of crack cocaine.3  See 21 U.S.C. §§ 841(a)(1),  841(b)(1)(B)(iii).  In due course, the appellant moved to  suppress both the drugs and his statements at the scene of the  highway stop.  After conducting an evidentiary hearing, the  district court denied the motion.  The court concluded that the  roadside confrontation had lasted no longer than five minutes  from start to finish; that this brief detention was reasonable,  given the patent motor vehicle violations; that the appellant  voluntarily consented to the pat-down search; and that, in all  events, the pat-down search and the questioning that followed  did not lead to the discovery of the contraband.  Rather, it was  the troopers' legitimate fear for their own safety, sparked by  Baker's movements, that prompted them to remove her from the car  and displayed the crack cocaine in plain view.  This, in turn,  gave rise to probable cause for the subsequent arrests and  interrogation.


11
Following some procedural skirmishing (not material  here), the case went to trial in September of 2000.  The jury  found the appellant guilty as charged.  The district court  thereafter classified him as a career offender and imposed a  228-month prison sentence.  This appeal ensued.  In it, the  appellant argues that the lower court erred both in denying his  motion to suppress and in fashioning his sentence.  We address  these assignments of error separately.

II.  THE FOURTH AMENDMENT ISSUE

12
When reviewing the district court's disposition of a  motion to suppress, we accept the court's findings of fact  unless clearly erroneous and evaluate its legal conclusions de  novo.  United States v. Sowers, 136 F.3d 24, 26 (1st Cir. 1998); United States v. Schaffer, 87 F.3d 562, 565 (1st Cir. 1996). Here, the appellant's principal contention is that impermissible  police tactics transformed a routine highway stop into an  unconstitutional fishing expedition -- an expedition that  ultimately led to the contraband and the confession.  To place  this contention into perspective, we begin by discussing the  legal framework surrounding such stops.  Moving from the general  to the specific, we then grapple with the various components of  the appellant's argument.


13
A.  The Legal Landscape.


14
A traffic stop, by definition, embodies a detention of  the vehicle and its occupants.  It therefore constitutes a  seizure within the purview of the Fourth Amendment.  Delaware v. Prouse, 440 U.S. 648, 653 (1979).  This means, of course, that the stop must be supported by a reasonable and articulable  suspicion of criminal activity, see Berkemer v. McCarty, 468  U.S. 420, 439 (1984), and that the detention must be reasonable  under the circumstances, United States v. Whren, 517 U.S. 806,  809-10 (1996).


15
Reasonable suspicion, as the term implies, requires  more than a naked hunch that a particular person may be engaged  in some illicit activity.  United States v. Sokolow, 490 U.S. 1,  7 (1989).  By the same token, however, reasonable suspicion does  not require either probable cause or evidence of a direct  connection linking the suspect to the suspected crime.  United  States v. Cortez, 449 U.S. 411, 417-18 (1981); United States v. Velez-Saldana, 252 F.3d 49, 52 (1st Cir. 2001).  Reasonable  suspicion, then, is an intermediate standard -- and one that  defies precise definition.  Its existence must be determined  case by case, and that determination entails broad-based  consideration of all the attendant circumstances.  Florida v. Royer, 460 U.S. 491, 500 (1983).  In mulling those  circumstances, an inquiring court must balance "the nature and  quality of the intrusion on personal security against the  importance of the governmental interests alleged to justify the  intrusion."  Sowers, 136 F.3d at 27 (quoting United States v. Hensley, 469 U.S. 221, 228 (1985)).  To keep this balance true,  the court must make a practical, commonsense judgment based on  the idiosyncracies of the case at hand.  Ornelas v. United  States, 517 U.S. 690, 695-96 (1996).


16
To work the calculus of reasonable suspicion in the  context of a traffic stop, an inquiring court must ask whether  the officer's actions were justified at their inception, and if  so, whether the officer's subsequent actions were fairly  responsive to the emerging tableau -- the circumstances  originally warranting the stop, informed by what occurred, and  what the officer learned, as the stop progressed.  Sowers, 136  F.3d at 27.  Formulating the answers to these queries demands a  margin of flexibility.  After all, while an officer's actions  must bear some relation to the purpose of the original stop, he  may shift his focus and increase the scope of his investigation  by degrees if his suspicions mount during the course of the  detention.  Id.; see also Terry v. Ohio, 392 U.S. 1, 10 (1968)  (observing that "the police are in need of an escalating set of  flexible responses, graduated in relation to the amount of  information they possess").


17
B.  The Merits.


18
In this instance, the appellant does not question the  legitimacy of the initial detention:  Holdsworth clearly had  cause to stop him for tailgating and operating an automobile  equipped with blue-tinted lights.  See supra note 1.  He asserts  instead that Holdsworth exceeded the scope of a permissible  traffic stop by conducting an unnecessary, unauthorized pat-down  search and wandering far afield in his questioning.


19
The appellant's thesis proceeds along the following  lines.  The pat-down search was involuntary, despite the  apparent consent, because Holdsworth still held the appellant's  license and registration, rendering the confrontation unduly  coercive.  Even if the frisk passes muster, this thesis runs,  Holdsworth's query about the bulge in the appellant's pocket was  beyond the pale because it did not pertain either to the  trooper's safety or to the underlying traffic violations. Moreover, the questions concerning the appellant's itinerary  also were out of bounds.  The combination of these toxic  ingredients -- the coerced pat-down search and the improper  questions -- impermissibly prolonged the detention and led  Holdsworth to call for assistance; the delay made Baker nervous,  inducing her to squirm in her seat; this fidgeting ultimately  led the troopers to the contraband; and that discovery prompted  the appellant's confession.  Cf. The Real Mother Goose 82-104  (1916) ("For want of a nail . . . . the kingdom was lost."). Thus, the appellant concludes, the district court should have  excluded the drugs and the incriminating statements as the  rotten fruit of a tainted traffic stop.


20
This argument is cleverly constructed and ably  presented, but it cannot withstand careful scrutiny.  In our  view, the consensual pat-down search was fully appropriate and  yielded information which gave Holdsworth reasonable suspicion  to continue on the minimally intrusive path that he chose to  pursue.  The questions that followed the frisk, though not  directly linked to the purposes of the stop, were reasonably  related to automobile travel in general and neither  fundamentally altered the nature of the detention nor  unreasonably prolonged it.  Thus, we reject the appellant's  argument.4


21
We start with the pat-down search -- which amounts to  a Terry stop within a Terry stop.  Normally, Holdsworth would  have needed some justification (such as a reasonable fear for  his own safety) beyond the traffic violations simplicter to  engage in it.  See Terry, 392 U.S. at 27.  In this case,  however, the appellant explicitly consented to the frisk.  The  district court found specially that this consent was voluntary. Unless this finding is clearly erroneous, we must accept it. See United States v. Coraine, 198 F.3d 306, 308-09 (1st Cir.  1999).


22
We discern no error.  Consent is voluntary if it is  "the product of an essentially free and unconstrained choice." Schneckloth v. Bustamonte, 412 U.S. 218, 225 (1973) (citation  omitted).  There is not a shred of evidence here that Holdsworth  tricked, threatened, or bullied the appellant into agreeing to  the pat-down search.


23
In an effort to fill this void, the appellant argues  that the situation itself was inherently coercive (and, thus,  that he could not have consented voluntarily).5  But the traffic  stop occurred in broad daylight, on a major thoroughfare.  At  the time of Holdsworth's request, his sidearm was holstered and  he was the only trooper present.  Although he still had the  appellant's license and registration in hand, that fact alone  does not vitiate the operator's consent.  See United States v. Purcell, 236 F.3d 1274, 1281-82 (11th Cir.) (holding consent to  search voluntary despite officer's retention of operator's  license and registration during traffic stop), cert. denied, 121  S. Ct. 2615 (2001); see also Florida v. Bostick, 501 U.S. 429,  435-36 (1991)(explaining that consent can be voluntary even  though the detainee does not feel free to leave); United States v. Barnett, 989 F.2d 546, 554-55 (1st Cir. 1993) (stating that  custody alone does not create the kind of coercive atmosphere  that abrogates consent).


24
The short of it is that, in most cases, the  voluntariness of consent is a matter of fact to be determined  from all the circumstances.  Schneckloth, 412 U.S. at 248-49. The district court obviously understood that reality and found  the facts with care.  Based on its supportable factual findings,  we uphold the constitutionality of the pat-down search.


25
In an effort to blunt the force of this conclusion, the  appellant argues that, even if his consent was validly obtained,  Holdsworth exceeded the scope of a consensual pat-down search. This argument hinges on the assertion that the trooper should  not have asked about the bulge in the appellant's pocket because  he knew that the bulge was not a weapon.  This argument  misconstrues applicable Fourth Amendment jurisprudence.  While  an officer may not seize an object during a Terry frisk unless  he has probable cause to believe that it is contraband, Minnesota v. Dickerson, 508 U.S. 366, 376 (1993); United States v. Schiavo, 29 F.3d 6, 9 (1st Cir. 1994), he is not prohibited  from inquiring, upon reasonable suspicion, into the nature of  that object.  So it was here:  the origins of the bulge were not  readily apparent -- it might well have been a weapon -- and  Holdsworth's question was directly pertinent to the safety  concerns that prompted his request for a pat-down search in the  first place.  We hold, therefore, that the trooper's inquiry was  well within the boundaries set by the Constitution.


26
We next proceed to the trooper's questions about the  appellant's peregrinations.  When the appellant explained that  he was carrying $2,000 in cash, Holdsworth's suspicions  understandably escalated.  Evaluating whether an officer's  suspicions are (or are not) reasonable is a fact-sensitive task,  bound up in the warp and woof of the surrounding circumstances. Royer, 460 U.S. at 500.  In carrying out that task, "[d]eference  is due to the experienced perceptions of the officer[]."  United  States v. Woodrum, 202 F.3d 1, 7 (1st Cir.), cert. denied, 531  U.S. 1035 (2000).  Mindful of that deference, we conclude that  the trooper's heightened suspicions (and, hence, his continued  questioning) were reasonable here.


27
The appellant resists this conclusion, insisting that  the mere possession of a large, unexplained amount of cash,  without more, cannot be the basis for heightened suspicion.  As  authority for this proposition, he cites Sokolow, in which the  Supreme Court indicated that paying for an airline ticket with  $2,100 in cash might be consistent with innocent travel.  490  U.S. at 9.  Contrary to the appellant's importunings, this  statement does not mean that the possession of a large,  unexplained sum of cash can never support reasonable suspicion.6 The circumstances matter, as does the degree of intrusiveness of  the continued detention.  See Lopez-Lopez v. Aran, 844 F.2d 898,  905 (1st Cir. 1988) (explaining that the degree of intrusiveness  of a stop must be proportional to the degree of suspicion that  prompted the intrusion); United States v. Berryman, 717 F.2d  651, 657 (1st Cir. 1983) (similar).  In the circumstances of  this case, we rule that the discovery of the cash justified a  brief period of additional questioning.  Cf. Conrod v. Davis,  120 F.3d 92, 97 (8th Cir. 1997) (holding that discovery of  $6,000 cash in a suspect's pocket and $4,000 in his suitcase  furnished reasonable suspicion).


28
This brings us to the nature of the questioning.  The  appellant asseverates that travel questions, unrelated to the  purpose of the original stop, are highly intrusive, unsupported  by reasonable suspicion of a separate crime, and therefore not  permissible in the course of the highway stop.  We disagree:  we  believe that this line of inquiry was lawful under the  circumstances.


29
The appellant strives to paint the picture in black and  white.  Citing cases such as United States v. Childs, 256 F.3d  559, 566 (7th Cir. 2001), and United States v. Holt, 229 F.3d  931, 936 (10th Cir. 2000),7 he asserts that an officer carrying  out a traffic stop must have some reasonable, substantial, and  independent source of suspicion about a different crime before  he can ask questions unrelated to the violation that justified  the stop in the first place.  But that depends on the nature of  the questions.  Both of the cited cases involved traffic stops  of persons previously suspected of other crimes, during which  the officers, for no apparent cause, began to ask directly  inculpatory questions involving the antecedent crimes.  See Childs, 256 F.3d at 561-62, 566 (involving questions about drug  possession during a stop for a broken windshield); Holt, 229  F.3d at 933, 940 (involving questions about weapons during a  stop for a seatbelt violation).  Such scenarios, in which an  officer stops a car for a minor traffic infraction and asks a  known suspect pointed questions about a serious crime unrelated  to the original violation, raise legitimate concerns about abuse  of authority.  See Whren, 517 U.S. at 810 (acknowledging the  temptation to use traffic stops as a means of investigating  unrelated criminal activity).


30
The case at bar does not lend itself to this sort of  black-and-white characterization, but, rather, involves more  muted shades of gray.  Here, the record contains no evidence  that the stop was a pretext to furnish the trooper with a forum  to ask questions about other crimes; prior to this encounter,  Holdsworth neither knew the appellant nor knew of him.  The  record is equally barren of any evidence that the trooper's  membership in the Enhanced Enforcement Unit impermissibly  colored his approach.  More important, Holdsworth did not stray  far afield, merely posing a few prosaic questions about the  appellant's itinerary:  where he and his passenger had been,  where they were going, and whether they had stopped along the  way.  Routine questioning of this sort, even when not directly  related to the violations that induced the stop in the first  place, is not uncommon during a highway stop.  See, e.g., United  States v. Johnson, 58 F.3d 356, 357 (8th Cir. 1995) (upholding  "routine questioning" about travel plans during stop for  speeding); United States v. Kopp, 45 F.3d 1450, 1454 (10th Cir.  1995) (similar).


31
To cinch matters, it was not until Holdsworth's  suspicions were aroused by the large, unexplained wad of cash  that his questioning expanded beyond the bare bones of the  traffic stop and the consensual frisk.  Since the trooper  lawfully learned about the cash -- the appellant, after all,  consented to the pat-down search and voluntarily described the  composition of the discerned bulge -- that discovery elevated his  suspicions to a degree sufficient to continue the detention  briefly and in a minimally intrusive way.  See Sowers, 136 F.3d  at 27 (approving increasingly intrusive unrelated questions  after suspicions escalated during a traffic stop); United States v. Barahona, 990 F.2d 412, 416 (8th Cir. 1993) ("If the  responses of the detainee and the circumstances give rise to  suspicions unrelated to the traffic offense, an officer may  broaden his inquiry and satisfy those suspicions.").  The travel  questions that followed were within the ambit of that authority,  and any effect they might have had on the duration of the  detention -- and the state of Baker's nerves -- was therefore  permissible.  Consequently, both the bag of crack cocaine and  the appellant's incriminating statements were lawfully obtained.

III.  THE SENTENCING ISSUE

32
The appellant's second complaint involves sentencing. Based on the weight of the seized crack cocaine, the district  court initially set the appellant's base offense level at 28. See USSG §§2D2.1(b)(1), 2D1.1(c)(6) (Nov. 1998).  The court then  determined that the appellant was a career offender and adjusted  his offense level to 34.  See id. §§4B1.1, 4B1.2.8  This yielded  a guideline sentencing range of 262-327 months.  The district  court departed downward, however, and imposed a sentence of 228  months.  See id. §4A1.3 (authorizing a downward departure if the  defendant's criminal history category significantly exaggerates  the gravity of his criminal past or the likelihood of  recidivism).


33
To be sure, the sentence seems severe.  But appellate  courts do not have the luxury of resolving sentencing appeals  based upon subjective value judgments.  The pivotal question,  then, is whether the sentence conforms to the guidelines.


34
The appellant posits that the district court  erroneously classified him as a career offender.  A defendant is  a career offender if "(1) the defendant was at least eighteen  years old at the time the defendant committed the instant  offense; (2) the instant offense of conviction is a felony that  is either a crime of violence or a controlled substance offense,  and (3) the defendant has at least two prior felony convictions  of either a crime of violence or a controlled substance  offense."  Id. §4B1.1.  The appellant unarguably meets the first  two benchmarks.  The issue here is whether the court  appropriately considered, as predicate offenses sufficient to  satisfy the third requirement, the appellant's prior convictions  for three counts of burglary of a commercial dwelling in  violation of N.H. Rev. Stat. § 635:1.


35
In the last analysis, the appellant's claim reduces to  his insistence that his prior state-court convictions for  commercial burglary should not count as "crime[s] of violence"  under the third furculum of the career offender guideline. Deciding where state-law crimes fit along a federal continuum is  tricky business.  In this instance, however, the decisional path  is well-trodden.  We conclusively answered the question that the  appellant seeks to raise in United States v. Fiore, 983 F.2d 1  (1st Cir. 1992).  There, dealing with a materially  indistinguishable Rhode Island burglary statute, we held that  burglary of a commercial premise constitutes a crime of violence  within the purview of the career offender guideline.  Id. at 4-5.


36
That effectively ends this aspect of the matter. Although the circuits are split -- some courts have followed Fiore's lead, see, e.g., United States v. Wilson, 168 F.3d 916,  926 (6th Cir. 1999); United States v. Haskell, 76 F.3d 902, 905  (8th Cir. 1996), whereas others have reached a different  conclusion, see, e.g., United States v. Spell, 44 F.3d 936, 938  (11th Cir. 1995); United States v. Smith, 10 F.3d 724, 732-33  (10th Cir. 1993) (per curiam)   we have stalwartly adhered to Fiore.  See, e.g., United States v. Sawyer, 144 F.3d 191, 196  (1st Cir. 1998).  This is in keeping with "the law of the  circuit" doctrine.  That doctrine holds a prior panel decision  inviolate absent either the occurrence of a controlling  intervening event (e.g., a Supreme Court opinion on the point;  a ruling of the circuit, sitting en banc; or a statutory  overruling) or, in extremely rare circumstances, where non-controlling but persuasive case law suggests such a course.  See Williams v. Ashland Eng'g Co., 45 F.3d 588, 592 (1st Cir. 1995). Neither circumstance exists here.


37
The appellant has two rejoinders.  First, he draws our  attention to Stinson v. United States, 508 U.S. 36 (1993), a  case in which the Supreme Court held that the Sentencing  Commission's guideline commentary comprises binding authority. Id. at 46-47.  Stinson does not aid the appellant's cause. Although Fiore drew on outside sources to elucidate the meaning  of the guidelines where the commentary was opaque, the Fiore court scrupulously applied the discerned dictates of the  commentary.  See Fiore, 983 F.2d at 4-5.  Thus, Stinson supports, rather than undermines, our prior decision.


38
The appellant next suggests that this court has  emasculated Fiore.  In an effort to sustain this suggestion, the  appellant cites two cases.  In the first, United States v. Peterson, 233 F.3d 101, 107-10 (1st Cir. 2000), we held that  breaking and entering without any intent to commit a crime is  not a violent felony under the Armed Career Criminal Act (ACCA),  18 U.S.C. § 924(e).  Unlike commercial burglary, however, the  breaking and entering charge in Peterson did not require proof  of specific intent.  The second case is also an ACCA case, United States v. Dueno, 171 F.3d 3 (1st Cir. 1999).  We  recognized there that, in certain circumstances, definitional  differences exist between the ACCA and the career offender  guideline.  Id. at 6.


39
We fail to see how either of these opinions casts doubt  upon Fiore   a guideline case.  In all events, over rulings by  implication are disfavored, and, in the best of circumstances,  a panel ought not lightly presume the implicit overruling of an  established circuit precedent.  See Stewart v. Dutra Constr.  Co., 230 F.3d 461, 467 (1st Cir. 2000).  We see no principled  basis for departing from the settled law of the circuit in this  instance.  Accordingly, we adhere to our prior holding that  burglary of a commercial premise is a crime of violence within  the purview of the career offender guideline.

IV.  CONCLUSION

40
We need go no further.  For the reasons stated, we  reject the appellant's attacks on both his conviction and his  sentence.


41
Affirmed.



Notes:


1
 For purposes of this appeal, the appellant effectively  concedes that he violated N.H. Rev. Stat. § 265:25.1 (ordaining  that "[t]he driver of a vehicle shall not follow another vehicle  more closely than is reasonable and prudent") and N.H. Rev.  Stat. § 266:74.ll (proscribing the use of blue-tinted lights on  vehicles other than law enforcement vehicles).


2
 They were correct.  Later analysis revealed that the  plastic bag contained twenty-eight grams of cocaine base.


3
 The grand jury indicted Baker as well, but the government  dropped that charge following her enrollment in a pretrial  diversion program.  She is not a party to this appeal.


4
 We are cognizant that our reasoning differs somewhat from  that of the district court, but we may affirm a district court's  suppression ruling on any ground made manifest by the record. See, e.g., United States v. Doe, 61 F.3d 107, 111-12 (1st Cir.  1995).


5
 The appellant also suggests that his consent was  involuntary because the trooper did not inform him that he could  decline to permit a search.  This suggestion overlooks that the  Supreme Court has held, recently and squarely, that an officer  conducting a highway stop need not inform the driver that he is  free to go before requesting permission to conduct a search. Ohio v. Robinette, 519 U.S. 33, 40 (1996).


6
 Indeed, in Sokolow itself the Court held that the cash  purchase, together with other indicia, supported a reasonable  suspicion sufficient to justify an investigative stop.  490 U.S.  at 11.


7
 We do not dwell on the appellant's reference to United  States v. Pruitt, 174 F.3d 1215 (11th Cir. 1999).  The stop  there lasted for nearly half an hour, id. at 1218, and the  Eleventh Circuit subsequently limited Pruitt to situations in  which the unrelated questions unreasonably prolonged the search. See Purcell, 236 F.3d at 1280.  Here, however, the district  court supportably found that the entire stop lasted no more than  five minutes, and there is no proof of unreasonable prolongation.


8
 The career offender guideline specifies an offense level of  34 where the statutory maximum sentence for the count of  conviction is 25 years or more (but less than life in prison). See USSG §4B1.1.  The statutory maximum for possession with  intent to distribute five grams or more of crack cocaine is 40  years.  See 21 U.S.C. § 841(b)(1)(B)(iii).


