A three-car crash in Rohnert Park early Friday morning partially blocked traffic on southbound Highway 101, slowing the morning commute and creating a back-up into south Santa Rosa past Todd Road, the CHP said.

No one was injured in the 6:43 a.m. crash north of Golf Course Drive, but the three involved vehicles were blocking the middle lane and part of the fast lane, Officer Steve Fricke said.

Authorities invoked a SIG alert because of stopped traffic and wreckage in the road.

The highway was cleared shortly after 7 a.m., the CHP said.

You can reach Staff Writer Mary Callahan at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahanB.