Icy roadways in parts of the Bay Area this morning resulted in some crashes and traffic slowdowns but no reports of injuries, according to the California Highway Patrol.

A large patch of black ice slowed traffic at a busy Walnut Creek intersection near Interstate Highway 680 and prompted warnings from police for motorists to drive carefully.

The ice patch, which formed at the intersection of Ygnacio Valley Road and Oakland Boulevard near the Walnut Creek BART Station, has since melted, according to police.

The water on the roadway came from a nearby water main break that occurred early this morning, East Bay Municipal Utility District spokeswoman Andrea Pook said. EBMUD crews were at the scene and will begin repairing the main tonight, she said.

Caltrans personnel responded to divert traffic around the ice.

Crews from Caltrans were also called this morning to Interstate Highway 280 in San Bruno, where several icy patches were reported between state Highway 92 and the Crystal Springs Road exit, CHP Officer Ron Simmons said.

Caltrans poured sand over the icy spots to make the roadway safe, he said.

Icy conditions on the Highway 280 Eugene A. Doran Memorial Bridge in San Mateo caused a solo-vehicle crash, Simmons said.

In Castro Valley, ice on the roadway near Five Canyons Parkway and Fairview Avenue caused one car to spin out, he said.

No injuries were reported in either incident.

CHP Golden Gate Division spokeswoman Sgt. Diana McDermott said black ice tends to form early in the morning on cold roadways that are covered by shadows, and on or around bridges.

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