A driver may have been blinded by the sun when he crashed a car into a horse-drawn carriage, injuring seven people on a Christmas Day hayride, police said Saturday.Richard Libby, 73, of Clinton, hit the rear end of the carriage carrying a driver and 14 passengers on Friday, smashing into it hard enough to break the driver's seat and send her sprawling, police said.One woman, 56-year-old Kathy Marciarille of Rome, Maine, was thrown from the carriage and run over by the car. She was hospitalized Saturday in critical condition at Maine Medical Center. Six other people were treated and released from hospitals.Police said it appears Libby, who was not injured, did not see the carriage until it was too late because of the angle and intensity of the sun; both vehicles were headed west around 2:30 p.m. when the crash occurred.Libby and carriage driver Cathleen Simmons, 42, were taken to a hospital to have their blood tested, which is routine, police said. It does not appear speed or alcohol was involved.Libby's car, a 2016 Chrysler sedan, will be inspected to see if there were any mechanical problems, police said.The carriage was giving rides to guests and volunteers at a Christmas dinner hosted at the Waterville Elks Lodge. Simmons told the Waterville Morning Sentinel she did not hear or see anything before the crash, her first."I'm always worried about it," she told the newspaper. "People fly by us like we weren't there."No charges have been filed and the investigation is continuing.