A rollover accident on the Saw Mill River Parkway during rush hour Thursday sent a woman to the hospital and caused massive backups on the road.

Westchester County police say Katharina Spinard was driving south of the Saw Mill Eastview exit in Elmsford around 9:30 a.m. when she lost control of her vehicle. According to police, Spinard?s car flipped over three times and landed on its roof.

Rescue crews say the 57-year-old Ossining woman was already unconscious when they arrived at the scene. Elmsford firefighters removed the car's rear windshield and extricated the driver.

Spinard was rushed to Westchester Medical Center with serious injuries. Police say wet roads and speeding may be to blame.