Southbound traffic on Highway 101 was briefly diverted early Sunday morning after a big rig driver hit a guardrail and spilled the contents of his fuel tank.

The 3:30 a.m. wreck was cleared relatively quickly and without much inconvenience to drivers due to the time, CHP Sgt. Ross Ingels said.

About 25 gallons of fuel spilled, but crews were able to keep it from spreading to nearby San Antonio Creek.

The truck driver apparently fell asleep and allowed his 20-foot truck and 53-foot trailer to drift into a guard rail near the Sonoma-Marin county line, Ingels said. San Antonio Creek runs nearby.

The driver, whose name wasn’t available, wasn’t hurt.

Officers diverted the light traffic to San Antonio Road until the fuel could be cleaned up. The trailer was empty.