Tiernan v. State, Department of Transportation, 2011 WY 143

Trooper Wagener observed Tiernan's vehicle cross the center line and drift toward the fog line, raising suspicion of impairment.
Trooper stopped the vehicle for a lane-use violation and suspected DUI.
Tiernan refused a breath test; WYDOT notified him of a six-month license suspension under impairment statutes.
Tiernan and counsel presented a patrol-car DVD at the hearing, arguing the stop was invalid based on the DVD.
OAH upheld the license suspension; Tiernan challenged in district court, which affirmed.
Wyoming Supreme CourtAffirmed: the stop was supported by substantial evidence and probable cause under the lane-use statute.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the DVD supports probable cause to stop Tiernan for lane violation	Tiernan: DVD contradicts trooper's lane-violation claim	Wagener: report and surrounding circumstances justify stop	Yes; substantial evidence supports stop based on observed lane violations and corroborating DVD

Dods v. State, 2010 WY 133 (Wyoming Supreme Court 2010) (clarifies reasonable suspicion and probable cause in traffic stops; mitigating factors)
Parks v. State, 2011 WY 19 (Wyoming Supreme Court 2011) (traffic stops as seizures; standard of review for reasonable suspicion/probable cause)
Damato v. State, 2003 WY 13 (Wyoming Supreme Court 2003) (establishes framework for stop based on traffic violations and proximity to oncoming headlights)
Lovato v. State, 2010 WY 38 (Wyoming Supreme Court 2010) (single observed violation can support stop)
Garvin v. State, 2007 WY 190 (Wyoming Supreme Court 2007) (driving too closely and lane usage considerations)
Fertig v. State, 2006 WY 148 (Wyoming Supreme Court 2006) (speeding as basis for stop when supported by circumstances)
Fender v. State, 2003 WY 96 (Wyoming Supreme Court 2003) (proximity to lines and lane deviations as justification)
Norman v. State, 747 P.2d 520 (Wyoming 1987) (early articulation on lane-of-travel violations)