EL SOBRANTE (CBS SF) — Twelve people were taken to hospitals Tuesday morning including a pregnant woman and seven children following a collision involving a school bus and three other vehicles in El Sobrante, California Highway Patrol officials said.

The collision was reported to the CHP at 8:11 a.m. at San Pablo Dam Road and Lois Lane.

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A Volkswagen Beetle was traveling north on San Pablo Dam Road in the far left lane with a Chevrolet Silverado behind it.

Both were approaching Lois Lane as a school bus was traveling south on San Pablo Dam Road in the far left lane and a Ford F-150 was beside it, traveling in the same direction.

CHP officials said the Volkswagen suddenly slowed to nearly a stop and the Chevy truck couldn’t slow down quickly enough to avoid hitting it.  The impact pushed the Volkswagen into the southbound lanes in front of the Ford, which T-boned it.

The driver of the Ford lost control, causing the Ford to spin out in front of the school bus, prompting the bus to collide with the Ford head-on.

Fire officials initially said three vehicles were involved in the collision but the CHP said four collided.

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The driver of the school bus, a woman who is 34 weeks pregnant, was taken to a hospital for precautionary reasons. Fire officials initially said she was injured.

Seven children on the bus were hospitalized for minor injuries and precautionary reasons.

The driver of the Volkswagen and one occupant of the Ford suffered major injuries.

Two others in the Ford and the driver of the Chevy suffered minor injuries.

CHP officials said the collision is still under investigation, but neither alcohol nor drugs appear to have played a part in the collision.

“Just driving behaviors,” CHP spokesman Officer Brandon Correia said.

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Anyone who witnessed the collision or the events leading up to it is asked to call CHP Officer Mendoza at (925) 646-4980.