On August 18, 1994, at 1907 Pacific daylight time, a Piper PA-12, N3415M, operated by its owner, experienced a total loss of engine power while cruising near Riverside, California. The pilot made a forced landing on a city street, and during rollout, collided with two occupied automobiles. The airplane was substantially damaged. The certificated airline transport pilot received minor injuries. No one on the ground was injured. Visual meteorological conditions prevailed at the time of the personal flight which originated from Lake Havasu, Arizona, at 1730. According to a police officer who responded to the accident site, fuel was observed in the street near the airplane. Under the direction of the National Transportation Safety Board, the airplane was examined by an airplane mechanic. The mechanic reported finding evidence of fuel in the airplane. No evidence was found of any mechanical problems with the airplane's engine. The mechanic reported that the engine appeared capable of producing power.