State v. K. Massey, 385 P.3d 544

At ~1:00 a.m., Trooper Bateman observed Massey’s SUV with black, logo-style tail light covers and stopped the vehicle because the covers appeared to obscure or diminish tail light visibility.
From about 500 feet behind the vehicle, Bateman testified the covers were "black and covered up the light" and diminished visibility; he stopped vehicles with such covers when able.
During the stop Bateman observed signs of drug impairment, asked Massey to exit, and saw a small plastic bag with possible drug residue in the passenger door pocket.
Massey denied the bag was his and refused consent to search; the vehicle was seized and later searched under warrant, yielding drugs, a handgun, and paraphernalia.
Massey moved to suppress, arguing Bateman lacked particularized suspicion to stop the vehicle because the covers allowed light through and did not “obscure” the lamps.
The District Court denied suppression; Massey entered a plea but reserved appeal of the suppression ruling. The Supreme Court of Montana affirmed.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether officer had particularized suspicion to stop vehicle for violating § 61-9-204(5) (tail lamp covers)	Bateman: observed covers obscuring/diminishing tail lamp visibility from ~500 ft, giving particularized suspicion of statutory violation	Massey: covers let light through and thus did not “obscure”; stop was part of a de facto zero-tolerance policy lacking individualized suspicion	Court: Affirmed—Bateman’s observations provided objective data supporting particularized suspicion of obscuring or diminishing visibility (statutory violation)

State v. Plouffe, 375 Mont. 429 (2014) (standards for reviewing suppression motions)
State v. Flynn, 359 Mont. 376 (2011) (particularized suspicion requires objective data and resulting inference of wrongdoing)
State v. Ross, 346 Mont. 460 (2008) (Fourth Amendment and investigatory stop principles)
State v. Duong, 378 Mont. 345 (2015) (inquiry focuses on facts available to the officer)