The 15-year-olds were trapped for a time under the driver's Nissan Sentra before being extricated by rescuers from the San Ramon Valley Fire Protection District, said Sgt. Phillip Wisotsky of the Danville Police Department.

One teen suffered a punctured lung and a broken bone, while the other youth's injuries consisted mostly of "road rash," Wisotsky said. They were taken to John Muir Medical Center in Walnut Creek, where police questioned them today.

"They said they had gone out into the street to look at the stars," Wisotsky said. "They laid blankets down ... fell asleep and got run over."

The incident occurred at 3:24 a.m. on Ashland Court. The driver, who delivers The Chronicle and other newspapers on the cul de sac, drove over the teens as she was leaving, apparently not seeing them.

Wisotsky said an investigation is under way "as to who is at fault. It is illegal to lay in the street. It is a public roadway and people aren't supposed to sleep on it."

According to Chris Blaser, vice president of circulation at The Chronicle, the driver was a subcontractor delivering papers for a Danville distributor.

"She is very shaken up," he said.

E-mail Elizabeth Fernandez at efernandez@sfchronicle.com.