LAKE ELSINORE (CNS) - A sedan slammed into the back of a tractor- trailer on Interstate 15 in Lake Elsinore today, injuring the car's driver. The collision happened about 10:55 a.m. on northbound I-15 at Nichols Road. According to the California Highway Patrol, the Toyota Camry rear-ended the semi's trailer in the slow lane, trapping the driver in the vehicle. Riverside County Fire Department crews freed the motorist from the wreckage, and an ambulance took the victim to Inland Valley Medical Center in Wildomar for treatment of unspecified injuries. The trucker was not hurt. The northbound slow lane was shut down during the operation.