Santa Rosa police cited four people on suspicion of driving on suspended licenses Tuesday in a courthouse sting targeting people convicted of drunken driving.

Undercover officers stationed throughout Sonoma County Superior Court watched 18 defendants go before judges, where they were warned not to drive, Sgt. Rich Celli said.

Fourteen of them walked out and did as they were told, taking buses, taxis or other forms of pre-arranged transportation, he said.

But four people hopped behind the wheels of cars and attempted to drive away, he said.

They were stopped by waiting officers, who cited them and impounded their cars, Celli said.

All had at least one prior drunken-driving conviction. They were Mercedes Jones, 40, of Sebastopol and Santa Rosa residents Teresa Sandoval, 32, Marco Martinez-Arteaga, 27, and Kristen Boyd, 26, Celli said.

The sting was one of about a half-dozen similar undercover operations at the courthouse every year.

It resulted in $4,400 in overtime expenses and was funded by a grant from the California Office of Traffic Safety.