Work crews are replacing the traffic signal, and police have closed both directions of Stevens Creek Boulevard in that area, police Sgt. Heather Randol said. The I-880 off-ramps there are also closed.
Stevens Creek Boulevard was expected to reopen around 6 p.m.
At 6:26 a.m., officers were dispatched to Stevens Creek at North Monroe Street, where the driver of a big-rig carrying a portable building had hit overhead equipment, downing some wires and taking out the signal, police said.
The truck driver suffered minor injuries, Randol said.
The big-rig involved in the accident was being followed by at least one other truck that was making the same trip, Randol said.
No lanes of Highway 880 were affected by the incident.
PG&E spokesman J.D. Guidi said that no power outages have been reported as a result of the crash, and that the wires that came down are not PG&E power lines.