A big rig rear-ended a car on Highway 4, causing a five-car pile-up.
According to California Highway Patrol Officer Daniel Sepulveda, the big rig was traveling at an unknown rate of speed near the South Filbert Street exit.
For unknown reasons, it couldn't stop during a slowdown ahead.
The big rig crashed into a Toyota Sequoia, which then created a domino effect with four other cars.
The driver of the Toyota Sequoia was taken to the hospital with major injuries.
The drivers of the other four cars suffered minor injuries.
The crash blocked the No. 2 and No. 3 lanes for a couple hours.
This is a developing story. Refresh this page for updates.
#trafficalert: Stockton: Eastbound SR-4 /X-town freeway # 2 & #3 lanes are blocked due to big rig accident use Alt. Route No ETO
— Caltrans District10 (@CaltransDist10) May 13, 2016