BYRON -- Four people, including a teenager, were hospitalized Wednesday morning after the driver of a minivan fell asleep at the wheel early Wednesday and collided with a big-rig on Byron Highway, a California Highway Patrol officer said.

Police believe the driver of the minivan, who was driving north from Los Angeles, fell asleep at the wheel about 5:23 a.m. and crossed over into the southbound lanes of the roadway just east of Bruns Road, CHP Officer John Fransen said. The minivan collided with the southbound big-rig, causing it to jackknife across the roadway.

Four people were injured in the crash, including a 14-year-old passenger in the minivan, Fransen said. The teen was airlifted to Children's Hospital Oakland with major injuries while the minivan's driver was taken in a separate helicopter to John Muir Medical Center in Walnut Creek.

The other two patients, the driver and a passenger in the big-rig, were taken to hospitals in Antioch, Evans said. The extent of their injuries was unknown as of 1 p.m. Wednesday.

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Contact Rick Hurd at rhurd@bayareanewsgroup.com. Contact Erin Ivie at eivie@bayareanewsgroup.com