Nine suspected drunken drivers were arrested around Sonoma County on Friday night as area police, the CHP and the Sheriff’s Office ramped up patrols for Fourth of July celebrations.

A 13-agency task force spearheads anti-drunken-driving efforts around the county. The numbers it released Saturday were provisional, with some agencies yet to report.

Arrests are up from last year, when seven drivers were arrested during the same period.

A drunken-driving sting in Santa Rosa on Friday night netted 28 arrests, five of them on suspicion of DUI, during the first night of what was expected to be a busy weekend for law enforcement officers.

The arrests came as a result of both special checkpoints and routine traffic enforcement.

In Santa Rosa, another nine people were arrested for driving on a suspended license, and 14 for driving without a license.

Three people — one from Santa Rosa, one from Fairfield and one from Vallejo — were arrested for other felony charges.

Police screened a total of 911 drivers in downtown Santa Rosa between 7 p.m. Friday and 3 a.m. Saturday.

Expanded patrols and checkpoints are expected to continue through Sunday.

Staff writer Jamie Hansen contributed to this report. You can reach Staff Writer Angela Hart at 526-8503 or angela.hart@pressdemocrat.com. On Twitter @ahartreports.