A Santa Rosa man who apparently fell asleep Monday morning while driving on Highway 12 triggered a five-vehicle collision that injured three people and closed the road for more than 90 minutes, the CHP said.

Wreckage was strewn down the two-lane highway west of Oakmont for about a quarter mile.

"It shut down both lanes for well over an hour. There was a lot of carnage on the road with five vehicles involved," said Santa Rosa Fire Battalion Chief Bill Shubin.

Traffic backed up for miles in both directions along the major eastside route.

"There is a route around; it's just a long one," CHP Officer Jonathan Sloat said.

The 9:06 a.m. crash began when Kyle Thompson, 25, of Santa Rosa was driving a family work truck.

He told officers he was tired and nodded off as he traveled east on Highway 12 between Oakmont Drive and Melita Road near Oakmont, CHP Officer Kerri Post said.

His 2003 Ford pickup drifted into the westbound lane and struck an oncoming big rig trailer, glancing off it and into oncoming traffic.

Annathea Henton, 41, of Calistoga saw the pickup coming into her lane and tried to swerve but couldn't avoid a head-on collision, Post said.

Her Toyota Highlander spun from the impact and was struck by a Toyota pickup driven by Erik Watkins, 38, of Santa Rosa. The Highlander then smashed into a telephone pole, snapping it, Post said.

The Toyota pickup then hit an oncoming 1999 Mercury Sable driven by Larry Stearley, 53, of Rohnert Park.

Thompson and Henton were taken to Santa Rosa Memorial Hospital where they were reported in good condition Monday evening.

A passenger in the Toyota pickup suffered a minor injury and also was taken to the hospital, Post said.

The Highlander, which had endured three separate collisions, ended up in a ditch, trapping Henton. Kenwood firefighters popped the door off to get her out.

"A lot of these cars these cars were pretty demolished," Sloat said.

The CHP closed Highway 12 in both directions until about 10:45 a.m.

Oakmont resident Marna Hill said she's worried about the number of collisions in the area of Oakmont and Highway 12.

Hill, who was at home at the time of the crash, said, "It sounded pretty awful."

Sloat noted there is a relatively high speed limit of 50 mph on a highway that lacks a divider between the lanes.

"We don't have many accidents in this area, but when we do, they're usually really serious," Sloat said.

You can reach Staff Writers Randi Rossmann at 521-5412 or randi.rossmann@pressdemocrat.com or Kevin McCallum at 521-5207 or kevin.mccallum@pressdemocrat.com. OnTwitter @citybeater