The California Highway Patrol says a tour bus crashed into the back of a big rig on Highway 99, sending 15 people to the hospital just after midnight Tuesday morning.
There were 33 people on the bus, including 3 children.
The driver of the big rig was among the 15 people were taken to the hospital and all are expected to recover.
Seventeen people were treated at the scene and released, including the driver of the bus.
Highway 99 was closed for a short time but has since reopened.