Although the following case did not take place in King County, it provides an interesting look at the constitutional protections against illegal search and seizure, and how a violation of those rights may overturn a DUI conviction in Washington or in any state.

Recently, an Arizona Court of Appeals threw out a drunk driving conviction after concluding that the arresting officer had to reason to pull the driver over in the first place. According to police reports, the man had been stopped by police because of a burned-out brake light. He had committed no other traffic violations or offenses. When the officer approached the vehicle, he allegedly began to suspect that the man had been drinking, and ultimately arrested him for DUI.

The man was eventually convicted of drunk driving while on a suspended license and sentenced to four months in jail and three years of probation. He appealed the conviction, arguing that he had two fully functional brake lights, and that the officer therefore had no reason to pull him over in the first place.

The appeals court agreed. In their ruling, they pointed out that a police stop is a seizure under the Fourth Amendment of the U.S. Constitution, and that police may only make such a seizure if they have a reasonable suspicion of criminal activity. The court stated that a missing brake light, especially when there are still two functional lights, does not constitute criminal activity. Therefore, the officer had violated the man's constitutional right against improper search and seizure, and the resulting DUI conviction must be overturned.

Source: Verde Independent, "Appeals court tosses DUI over brake lights interpretation," Howard Fischer, Dec. 20, 2011