A big rig towing a trailer was blocking most of northbound Highway 99 on Tuesday after it crashed south of the Mission Avenue exit, according to California Highway Patrol.
No injuries were reported, CHP said, but traffic slowed to a crawl as officers directed commuters around the trailer and onto the center divide. The accident was reported about 4 p.m., according to CHP.
It was not immediately clear how long it would take to clear the highway.
--Update at 5 p.m.--
CHP says they hope to open two lanes in the next 15 minutes or so.
More on this as information becomes available.