State v. Johnson, 370 N.C. 32

Snow fell and slush formed; Johnson’s truck was stopped at a red light.
When light turned green, Johnson abruptly accelerated, turned left, and fishtailed in front of a nearby patrol car.
Officer Gardin stopped Johnson for driving at an unsafe speed given road conditions.
Superior Court denied suppression on remand after Johnson pleaded guilty; Court of Appeals later reversed, finding the stop unconstitutional.
North Carolina Supreme Court reverses, holding officer had reasonable suspicion to stop Johnson under the totality of circumstances.
Findings of fact show snow, reduced traction, abrupt maneuver, and loss of control that supported reasonable belief of unsafe driving under §20-141(a).

Issue	Plaintiff's Argument	Defendant's Argument	Held
Was there reasonable suspicion to stop for unsafe driving?	Johnson contends there was no actual violation observed.	Johnson argues the stop was not supported by reasonable suspicion.	Yes; stop supported by reasonable suspicion.
May reasonable suspicion be based on observed conduct suggesting a violation even if no exact violation is proved?	Johnson argues no violation was observed, thus no basis for stop.	Johnson seeks to limit stop to actual violations only.	Yes; reasonable belief suffices for reasonable suspicion.

State v. Styles, 362 N.C. 412, 665 S.E.2d 438 (N.C. 2008) (reasonable suspicion standard applies to traffic stops)
United States v. Delfin–Colina, 464 F.3d 392 (3d Cir. 2006) (officer need only reasonably believe a violation occurred)
United States v. Chanthasouxat, 342 F.3d 1271 (11th Cir. 2003) (reasonable belief governs traffic stop even if no actual offense proven)
Cashman, 216 F.3d 582 (7th Cir. 2000) (Fourth Amendment requires reasonable assessment of facts, not perfect accuracy)