An Ashland father, his daughter and her two grandparents were killed when two big rigs slammed into their car stopped in traffic near Napa, Calif. Thursday, the California Highway Patrol said.

An Ashland father, his daughter and her two grandparents were killed when two big rigs slammed into their car stopped in traffic near Napa, Calif. Thursday, the California Highway Patrol said.

Ashland resident Matthew Jay Smith, 48, was driving the Subaru Forester when it was rear-ended by a big rig, thrust into oncoming traffic and broadsided by another big rig at 8:20 a.m. on Highway 12 in American Canyon.

Also killed were Smith's daughter, 19-year-old Laura Smith of Downingtown, Pa., and Smith's parents, 80-year-old Richard Smith and 74-year-old Sally Smith, of Simsbury, Conn.

"They were definitely killed on impact," said CHP Officer Ryan O'Day. "They were pretty much either at a stop or a slow because of traffic and basically this 18-wheel vehicle pushed them into the east side of traffic, where they were broadside by another 18-wheel vehicle."

According to the San Jose Mercury News, the family was planning to see the Napa Valley wine country, before traveling north to Oregon.

Matthew Smith was driving the car, with his daughter Laura seated in the front passenger seat and the two grandparents in the back, according to the newspaper.

The Subaru was traveling west on the two-lane Highway 12, near Interstate 80, which connects Sacramento and San Francisco, O'Day said.

He said all four family members were killed upon impact of the second 18-wheel truck, which was fully loaded and was carrying concrete pipes. Emergency workers shut down the highway for about three hours Thursday morning, while they worked to extricate the bodies from the car, O'Day said.

The CHP determined the driver of the first big rig, 42-year-old Gustavo Lopez of San Bernardino, Calif., was at fault in the crash. He suffered minor to moderate injuries.

The driver of the second truck was not hurt.

O'Day said alcohol or drugs were not believed to have been a factor in the crash.

Contact staff writer Hannah Guzik at 482-3456 ext. 226 or hguzik@dailytidings.com.