On June 14, 1998, at 1655 hours Pacific daylight time, a Boeing Stearman A75N1, N48576, struck a vehicle on approach for landing and came to rest inverted on the runway of a private dirt strip near Riverbank, California. The aircraft, operated under 14 CFR Part 91 sustained substantial damage. The commercial pilot/owner was not injured. The driver of the car sustained minor injuries. Visual meteorological conditions existed for the personal flight that had departed the Sacramento, California, airport at 1645. The flight was scheduled to terminate at the private dirt strip and no flight plan was filed. In an interview with a Federal Aviation Administration (FAA) inspector, the pilot stated that the dirt strips runs perpendicular to Lone Star Road. His standard practice is to overfly the airport two times to check the windsock for landing direction, and to verify that there is no traffic on the road. He reported that as he reached the threshold "things happened." The aircraft touched down and became inverted facing the approach end of the runway. The pilot reported that he exited the aircraft to see if he had touched down on soft dirt. He stated that he still had not realized that he had struck a vehicle. The pilot reported no pre-existing anomalies with the engine. In the pilot's written statement to the Safety Board, he stated that to clear traffic on the road, his usual practice is to fly approximately 200 to 300 feet above ground level. He further reported that he observed no traffic on the base leg or final leg of the approach. A California Highway Patrol (CHP) officer from Colusa County investigated the accident, and interviewed the pilot and driver of the car. Both the pilot and the driver of the automobile stated that they were unaware of each other's presence during the accident. The CHP officer noted that there are no signs either north or southbound warning of low flying aircraft, or any mention of an airport until arrival at airport entrance. The driver of the vehicle was interviewed by the FAA through his father. The father reported that his son was traveling southbound at the time of the accident, and the aircraft struck the left side of the vehicle.