The airplane was substantially damaged at 1545 Central time during an off-airport forced landing. The solo pilot sustained minor injuries and five persons on the ground sustained minor injuries. Visual conditions prevailed. The airplane was in cruise flight at 4500 feet msl when the right side cockpit canopy suddenly opened and remained open at approximately a 90-degree-up position. The pilots headset and several loose items immediately departed the cockpit. Debris struck and damaged the rear-mounted propeller, separating approximately half of one propeller blade and resulting in a “large vibration.” The pilot began a descent and headed toward the nearest airport but the engine failed. The pilot executed a forced landing on a busy five-lane road. After missing several other vehicles, the airplane struck and damaged the rear of an automobile. The airplane then struck several sign posts and came to rest partially nose-down in a ditch.
