Illinois v. Lidster
United States Supreme Court
540 U.S. 419 (2004)
One week after an unidentified motorist fatally struck a postal worker on an Illinois highway at night, police set up a checkpoint at roughly the same location and time, briefly stopping each vehicle for 10 to 15 seconds to ask if occupants had information about the accident and to hand out flyers; Lidster (defendant) swerved before the checkpoint, narrowly missing an officer, and after officers smelled alcohol on his breath and administered a sobriety test, he was arrested and later convicted of driving under the influence. The Illinois Supreme Court found the stop unlawful under City of Indianapolis v. Edmond's rule against general crime-control checkpoints, and the U.S. Supreme Court granted certiorari.
Whether a roadside vehicle checkpoint is presumptively unlawful when its primary law-enforcement purpose is to ask vehicle occupants for information about a crime possibly committed by others, rather than to search for evidence of the stopped motorists' own wrongdoing.