HAYWARD (CBS SF) — Two people died in a horrific four-vehicle crash on Highway 880 that shut down all northbound lanes overnight as California Highway Patrol officers investigated the accident.

The CHP said it was hopeful the lanes would reopen by 6 a.m. for the Wednesday morning commute.

The collision was first reported around 10:40 p.m. Tuesday and involved at least four vehicles, including a big rig and tour bus. According to the CHP, the victims who died were driving in separate motor vehicles, not the big rig or tour bus.

Investigators believe the tour bus was in the center lane when it came upon stop-and-go traffic and plowed into the rear of a vehicle. It then crashed into a second vehicle, traveling a short distance on top of that vehicle until finally slamming into a truck.

Fortunately, investigators said, there were no passengers in the tour bus.

Drugs and alcohol do not appear to have played a role in the crash.

A map of the area affected by multi-vehicle crash. (Sigalert screenshot)

Motorists were advised overnight to expect delays and to use alternate routes.