State v. Nathan David Neal, 362 P.3d 514

Around midnight on Nov. 14, 2012, Boise PD Officer Thueson followed Nathan Neal after observing Neal’s pickup twice drive onto (but not across) the right-edge roadway line (a fog/edge/bike-lane line) roughly one mile apart; no other erratic driving was observed.
Thueson stopped Neal after a right turn onto Gary Lane; the stop led to Neal’s DUI arrest. Neal received no traffic citation at the scene.
Neal moved to suppress evidence, arguing the stop lacked reasonable articulable suspicion; the magistrate granted suppression, finding no traffic violation and no reasonable suspicion of DUI.
The State appealed; the district court reversed, concluding driving on the line violated Idaho Code § 49-637 (lane maintenance) and Boise City ordinance (bike-lane) and therefore justified the stop; Court of Appeals affirmed.
The Idaho Supreme Court granted review, upheld the magistrate on the DUI and Boise‑ordinance issues, and reversed the district court on whether touching the right-edge line violates § 49-637, holding that driving onto but not across the right-edge line does not violate the statute and therefore did not justify the stop.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether two brief instances of driving onto the right-edge line (one mile apart, near midnight) gave reasonable suspicion of DUI	Neal: two brief touches do not fall outside the broad range of normal driving; not enough for DUI suspicion	State: the two instances, time of night, and proximity justify reasonable suspicion of intoxication	Held: No. Two brief touches, without more, are insufficient to create reasonable suspicion of DUI
Whether the Boise City ordinance (driving in bicycle lane) justified the stop	Neal: magistrate found no evidence the incidents occurred in Boise, so city ordinance not established	State: the conduct occurred in Boise and violated Boise City Code § 10-10-17	Held: Court defers to magistrate’s factual finding that city was not proved; Boise ordinance not considered to justify stop
Whether driving onto (but not across) the right-edge/fog line violates Idaho Code § 49-637 (drive within a single lane)	Neal: § 49-637 should not be read to make mere touching of an edge/ fog line a lane violation; ambiguous statutory text supports a reasonable construction avoiding harsh consequences	State: edge/ fog lines are not part of the lane; driving on them means leaving the lane, violating § 49-637	Held: The Court construed § 49-637 as not prohibiting driving onto but not across the right-edge line; touching the edge line does not violate the statute and thus cannot justify the stop

State v. Henage, 143 Idaho 655 (Idaho 2007) (traffic stops are seizures under the Fourth Amendment)
Delaware v. Prouse, 440 U.S. 648 (U.S. 1979) (random stops are seizures; Fourth Amendment limits)
State v. Emory, 119 Idaho 661 (Idaho Ct. App. 1991) (brief touching of fog line with vehicle in proper lane insufficiently suspicious for DUI)
State v. Flowers, 131 Idaho 205 (Idaho Ct. App. 1998) (multiple factors—weaving, crossing lines, hugging fog line—may together create reasonable suspicion of DUI)
United States v. Colin, 314 F.3d 439 (9th Cir. 2002) (brief line touches after legitimate lane changes insufficient for DUI suspicion)
United States v. Lyons, 7 F.3d 973 (10th Cir. 1993) (minor deviations from a perfect vector do not alone support reasonable suspicion of impairment)
United States v. Alvarado, 430 F.3d 1305 (10th Cir. 2005) (crossing the fog line and driving onto the shoulder supports enforcement action)