A malfunctioning signal near the foot of Dumbarton Bridge caused massive traffic jams in parts of Palo Alto and Menlo Park at the start of the afternoon commute Thursday and continued into the evening.
According to Menlo Park police, the signal light at Bayfront Expressway and University Avenue went out shortly before 4 p.m. In a news alert, police said the problem was caused by a "PG&E issue" that was later identified as a power outage. Officials estimated the problem will be resolved by 8 p.m.
Menlo Park police later sent a message after 6:30 p.m. that signals are functioning again, but motorists were advised to expect continued traffic delays until traffic clears out.
The problem significantly worsened what was already a congested commute, with residents reporting significant backups along Middlefield Road. Traffic maps showed red lines -- connoting severe jams -- along major arterials and freeways -- including Middlefield and University Avenue, Bayfront Expressway and Willow Road, El Camino Real through Menlo Park and East Palo Alto.
Palo Alto police also sent out a traffic advisory, reporting "heavy delays throughout Palo Alto" due to the signal malfunction.