Sebastopol police set up a drunken driving checkpoint at the eastern entrance to town Saturday night, screening 900 drivers in about five hours.
Officers arrested one person suspected of driving impaired and cited eight unlicensed drivers.
The checkpoint was held at Sebastopol and Barnes avenues from 6:20-11:30 p.m.
The vast majority of drivers were stopped for a brief time before being sent through the checkpoint. Seven drivers were given a closer look for being impaired, leading to the one arrest.
Officers also checked the license status of 75 drivers and found eight who were behind the wheel despite not being valid drivers and one with a suspended license.
They cited one driver suspected of possessing marijuana and one for violating a restraining order, according to police.
Grant money from the California Office of Traffic Safety paid Sebastopol police to run the checkpoint.