On August 15, 2000, at 1003 hours Pacific daylight time, an amateur-built Follmer Q200 airplane, N8427, collided with ground obstructions during a forced landing on an interstate highway in Corona, California. The forced landing was precipitated by an in-flight separation of a portion of one propeller blade. The aircraft was operated by the pilot under the provisions of 14 CFR Part 91 of the Federal Aviation Regulations. The airplane was destroyed in the accident sequence. The commercial pilot, the sole occupant, sustained minor injuries. Visual meteorological conditions prevailed for the local area personal flight that had originated from the Chino, California, airport about 0945. An Federal Aviation Administration (FAA) airworthiness inspector from the Riverside, California, Flight Standards District Office responded to the accident site and examined the airplane and interviewed the pilot. The pilot reported that the airplane was in cruise flight when it suddenly began to shake violently. The pilot believed he had lost part of the wooden propeller and turned to return to the Chino airport. The shaking through the airframe became intense and the pilot was unsure of the continued integrity of the airframe. He decided to land on a major interstate highway beneath the airplane. During the landing rollout, the airplane was quickly catching up to automobiles on the road ahead and the pilot intentionally steered the airplane to the right shoulder to avoid a collision with the vehicles. The right wing contacted a light pole and slued the airplane nose first into another pole. The second collision with the pole shattered the propeller into small splinters. The airplane continued down an embankment and collided with additional brush. The FAA inspector searched the area and was able to identify one propeller blade tip in the propeller fragments scattered over the site. The second tip could not be located. According to the pilot, the aircraft owner built the airplane prior to 1990 and obtained an initial airworthiness and registration certificate, then placed the airplane into storage in a hangar at the Chino airport. The airplane did not fly from 1990 until weeks before the accident. The pilot was in the process of flying the initial 40 operating hours for an unrestricted experimental airworthiness certificate and had flown the airplane about 11 hours.