DARIEN, Ill. (STMW) — A 20-year-old woman and her baby are expected to survive after the car they were in went off a bridge Saturday night on Route 83 and onto the southbound lanes of the Stevenson Expressway.

About 11 p.m., the car was traveling southbound on Route 83 when the driver, a mother with her baby in the car, lost control, hit a guard rail and plummeted off the over pass onto the southbound lanes of Interstate 55, Illinois State Police Elgin District Master Sgt. Bart Lamb said.

The car, a 1999 Toyota of an unidentified model, ended up on its roof, Lamb said.

The 20-year-old woman suffered a broken back and lacerations, Illinois State Police Elgin District Sgt. Robert Satkiewicz said. She was airlifted in “stable” condition to Advocate Good Samaritan Hospital in Downers Grove. The baby suffered a fractured skull and was taken to Good Samaritan in “stable” condition and later transferred to Advocate Lutheran General Hospital in Park Ridge.

The crash occurred between Willowbrook and Burr Ridge, Satkiewicz said. It was not known if the woman might have fallen asleep while driving.

The accident is under investigation, Lamb said.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2010. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)