Commonwealth v. Livingstone v. Aplt., 11 WAP 2016

Victoria Livingstone was stopped on Interstate 79 at night in a running, stationary vehicle while attempting to program her GPS. Trooper Frantz pulled alongside and activated emergency lights before approaching.
At a suppression hearing, trooper testified he activated lights as a safety precaution for himself, other motorists, and the stopped driver.
Livingstone moved to suppress evidence obtained following the encounter, arguing the trooper’s activation of emergency lights and approach constituted a seizure (an investigative detention) under the Fourth Amendment.
Trial court and Superior Court concluded the trooper’s approach was a mere encounter or a safety check; suppression was denied and the Superior Court’s decision was affirmed below.
The Pennsylvania Supreme Court majority held the activation of emergency lights transformed the encounter into a seizure; Justice Mundy dissented, arguing the totality of circumstances showed only a mere encounter and would have affirmed without addressing community-caretaking.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Trooper Frantz’s activation of emergency lights and approach constituted a Fourth Amendment seizure (investigative detention).	Livingstone: lights + trooper pulling alongside an already-stopped car amounted to a show of authority that a reasonable person would not feel free to decline, thus a seizure.	Trooper/Livingstone (as to intent): lights were used as a safety measure on a busy interstate; no coercive language, weapon display, blocking, or physical contact — totality shows a mere encounter.	Majority: activation of emergency lights converted the encounter into a seizure. Dissent (Justice Mundy): under the totality of circumstances it was a mere encounter.
Whether it was necessary to recognize or apply a community-caretaking exception to justify the trooper’s conduct.	Livingstone: (implicit) seizure analysis controls; community-caretaking not invoked to validate a seizure.	Trooper/State: even if seizure, community-caretaking could justify officer’s conduct (but dissent says unnecessary to reach).	Majority addressed community-caretaking; dissent would decline to reach it because no seizure occurred.

Commonwealth v. Lyles, 97 A.3d 298 (Pa. 2014) (totality-of-circumstances test for seizure analysis)
United States v. Mendenhall, 446 U.S. 544 (U.S. 1980) (factors indicating a show of authority include multiple officers, display of weapon, physical touching, tone or language implying compulsion)
Brendlin v. California, 551 U.S. 249 (U.S. 2007) (reasonable-person test: would a person feel free to terminate the encounter)
Commonwealth v. Au, 42 A.3d 1002 (Pa. 2012) (officer’s use of headlights/flashlight to illuminate a parked car at night was a mere encounter, not a seizure)
Pennsylvania v. Mimms, 434 U.S. 106 (U.S. 1977) (recognition of inherent dangers of traffic stops)