A car fire on Interstate 580 in Dublin late Monday morning sparked a blaze on an adjacent grassy hillside and backed up traffic into Castro Valley.
The car fire was on the eastbound side of the interstate just west of the .
The car fire began about 11:40 a.m. The grass fire burned about an acre. After the blaze was extinguished, firefighters blocked off the right lane to mop up.
All the action in the area clogged traffic almost to Castro Valley Boulevard as of 1 p.m.
Patch will update this story when further details are available.