question of law and fact that we review de novo. See Ornelas v. United States, 517 U.S. 690, 699, 116 S.Ct. 1657, 134 L.Ed.2d 911 (1996).
The Fourth Amendment prohibits “unreasonable searches and seizures.” U.S. Const, amend. IV. And, it is well settled that a search conducted without a warrant is per se unreasonable unless it falls within one of the “well-delineated exceptions” to the warrant requirement.
Katz v. United States, 389 U.S. 347, 357, 88 S.Ct. 507, 19 L.Ed.2d 576 (1967). One such exception is the authority of law enforcement officers to effect a limited investigatory detention when they possess “a reasonable and articulable suspicion that the person seized is engaged in criminal activity.”
Reid v. Georgia, 448 U.S. 438, 440, 100 S.Ct. 2752, 65 L.Ed.2d 890 (1980) (per curiam);
see Terry v. Ohio, 392 U.S. 1, 21-22, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968). A reasonable, articu-lable suspicion is “ ‘a particularized and objective basis’ for suspecting the person stopped of criminal activity.”
Ornelas, 517 U.S. at 696, 116 S.Ct. 1657 (quoting
United States v. Cortez, 449 U.S. 411, 417, 101 S.Ct. 690, 66 L.Ed.2d 621 (1981)). In determining whether a detention is supported by reasonable suspicion, we look to the circumstances known to the officer and “the specific reasonable inferences which he is entitled to draw from the facts in light of his experience.”
Terry, 392 U.S. at 27, 88 S.Ct. 1868. In so doing, we must consider “the totality of the circumstances-the whole picture.” Cortez, 449 U.S. at 417, 101 S.Ct. 690.
A.
Emphasizing the general principle that individuals have a right to avoid encounters with the police, see, e.g., United States v. Burton, 228 F.3d 524, 527, 528-29 (4th Cir.2000), Smith asserts that a motorist “should be free to avoid a police encounter at [a] roadblock by stopping and turning around, so long as he does so legally.” Br. of Appellant at 21. Smith argues that a motorist’s legal turn to avoid a police roadblock cannot create reasonable suspicion of criminal activity because the driver may be turning away from the roadblock for innocent reasons. By contrast, the Government maintains that when police reasonably suspect that a driver is attempting to avoid a roadblock, they may stop the driver to ascertain the reason for that avoidance.
We find instructive the decision of the Supreme Court in Illinois v. Wardlow, 528 U.S. 119, 120 S.Ct. 673, 145 L.Ed.2d 570 (2000). In Wardlow, two Chicago police officers were part of a police caravan patrolling a high-crime area investigating drug transactions. See Wardlow, 528 U.S. at 121, 120 S.Ct. 673. One officer observed Wardlow standing next to a building holding an opaque bag. See id. at 121-22, 120 S.Ct. 673. Wardlow looked in the officers’ direction and fled. See id. at 122, 120 S.Ct. 673. The officers followed Ward-low in their patrol vehicle and eventually stopped him. See id. Upon conducting a protective patdown search of Wardlow, the officers discovered a loaded handgun in Wardlow’s bag and arrested him. See id. After moving unsuccessfully to suppress the handgun, Wardlow was convicted of a weapons charge in Illinois state court. See id. The Illinois appellate courts, however, reversed Wardlow’s conviction on Fourth Amendment grounds, holding that the weapon should have been suppressed because the officers lacked reasonable suspicion to stop Wardlow. See id. at 122-23, 120 S.Ct. 673.
The Supreme Court reversed. The Court initially noted that Wardlow’s presence in a high-crime area, while not dis-positive, was a relevant factor in the rea