Route 9W southbound, just after Mountain Road, was closed for about 90 minutes while an accident was cleared earlier this morning. A vehicle rolled over shortly before 9 a.m. after the driver failed to negotiate a turn. The vehicle overturned and was wedged in a rock formation. One occupant was observed being extricated from the vehicle. He seemed alert as he was lifted on a stretcher. The driver was transported to Westchester Medical Center.