A 6-year-old Spring Valley girl was injured Wednesday when she was struck by a California Highway Patrol cruiser. The CHP car was headed west on Troy Street east of Sweetwater Road at 5:20 p.m. when the girl darted into the street, said CHP spokesman Don Maxfeldt. Amy Walsh was taken by Life Flight helicopter to Children's Hospital, where she underwent emergency surgery and was listed in serious condition. CHP officer Steve Young was responding to a traffic collision--but was traveling within the posted speed limit of 30 m.p.h.--when he hit the girl, Maxfeldt said. Young only had time enough to brake and attempt to swerve the vehicle, Maxfeldt said. The road surface was damp at the time, but visibility was good. The incident is being investigated by the CHP.