A power outage today knocked out power to multiple traffic signals along MacArthur Boulevard, making for a rough drive in the area for about two hours, a police official said.

The outage was reported about 11:45 a.m. when motorists began noticing traffic signals not functioning properly, according to Kathy Lowe, spokeswoman for the Newport Beach Police Department. Power was restored about 3:30 p.m.

"We are unsure what caused the power outage," Lowe said.

Newport Beach police sent out a Nixle alert about 1 p.m. directing motorists to avoid MacArthur Boulevard at Ford Road due to heavy traffic congestion caused by the outage. As of 4 p.m. traffic was cleared and the signals were back to normal, Lowe said.