The CHP received a report of fallen wires just before 3 p.m. near the Millbrae exit. Firefighters, PG&E crews and the CHP responded to the scene.
Lanes on both sides of the freeway were closed off and on throughout the afternoon as crews worked to clear the phone line from the roadway.
CHP officials believe that the downed lines may have been the result of a hit in run accident in which a gray flat bed truck struck a utility pole. They are looking for the truck and its driver. The truck's license plate number is 4R23454.
Motorists have been advised to use Interstate Highway 280 as an alternate route, Bartlett said.
Bay City News contributed to this report
