Before law enforcement can determine whether a driver is legally impaired, the policeman or deputy must stop the vehicle and/or assess the driver's condition. But authorities can't just target random vehicles in an effort to find drunk or drugged drivers; they must have probable cause to do so. And that can't happen without reasonable suspicion that the driver is impaired.
That's why a convicted drunk driver in Nebraska had his offense overturned on appeal this week.
In September 2013, Adam Woldt was driving when he was forced to stop behind a truck that had already been pulled over by a cop. Because he was unable to get by, he began backing up - but stopped when the policeman raised a hand and ordered him to do so.
In court, the lawman testified that he was hoping to ask Woldt whether he had seen the truck run over some traffic cones on a nearby street. But when he smelled alcohol, he conducted sobriety tests on Woldt and arrested him on drunk driving charges. Woldt's BAC was measured at .148, and he was eventually convicted of DUI.
But the defendant argued that his Fourth Amendment rights were violated because the officer had arrested Woldt after an unlawful "search" because he never suspected that Woldt was drunk when he stopped him. The Nebraska Court of Appeals agreed and vacated Woldt's DUI conviction.
Such reversed verdicts are rare, but they're much more likely to occur if the accused engages the services of an experienced DUI defense attorney after being arrested and charged with driving under the influence.