At about 1830 Pacific time, the pilot attempted to make an emergency landing on a highway following a flight-control malfunction. During the attempt, the left main landing gear was sheared off after it struck the top of a moving truck and the left wing was damaged when it struck a fence pole. The solo commercial pilot and the two occupants in the moving truck were not injured. The airplane sustained substantial damage. Visual conditions prevailed. About 30 minutes after takeoff, the pilot felt a “bad vibration from the tail.” When he looked back he saw the left elevators trim tab oscillating up and down. He reduced the power and was about to search for an alternate airport using a GPS navigator when his avionics failed. He then attempted a landing on the highway.