Michelle Hadley, 32, was flown to John Muir Medical Center in Walnut Creek after the 10:20 a.m. crash. Hospital spokesman Ben Drew said she was in critical condition this afternoon.
The CHP received a call about a reckless driver who was speeding, using all lanes and tailgating on I-80 near Alamo Road in Vacaville.
As the 1998 Lexus GS400 passed Airbase Parkway, the car left the north edge of the road and traveled west in a drainage ditch along the shoulder of the freeway, according to the CHP.
The Lexus struck a berm at the end of the ditch, became airborne, rotated to the right and flipped over as it cleared a 15-foot perimeter fence, the CHP said.
The car landed on its wheels in the backyard of a residence on Alford Drive in Fairfield, according to the CHP.
The Fairfield Fire Department extricated Hadley from the Lexus and she was flown to the hospital, the CHP said.
It is unknown if drugs or alcohol were involved in the crash, the CHP said.