Napa, California Roadblocks
Not specifying time or place but they do these every month when they aren’t doing saturation patrols instead. They go after anyone who tries to turn around for an illegal U-turn. It is noticed as a single checkpoint but appears that more than one checkpoint is set up at once on opposite sides of town simultaneously. This sobriety checkpoint is often noticed in newspapers within Napa County (such as Vallejo and Calistoga papers) and not noticed in the Napa Register local paper to decrease awareness of checkpoint without strictly violating any notice requirements attendant on the police.