On October 23, 1999, at 0959 central daylight time, a Wright Avid Flyer Mark IV homebuilt airplane, N583AF, was substantially damaged upon impact with terrain while landing on a road near Seabrook, Texas. The pilot, sole occupant of the airplane, was not injured. The airplane was owned and operated by the pilot. Visual meteorological conditions prevailed for Title 14 CFR Part 91 local personal flight for which a flight plan was not filed. The flight originated from the Johnnie Volk Field Airport (37R), near Hitchcock, Texas, at 0900. The 900-hour pilot reported that the 2-cylinder Rotax engine developed a vibration during flight. The pilot stated that the vibration was accompanied by a rise in cylinder head temperature, so he elected to perform a precautionary landing on a westerly heading on a nearby dirt road to investigate the source of the engine problem. The pilot, who had accumulated over 400 hours in the airplane, stated that he was expecting a crosswind landing; however, the wind speed and direction were different than anticipated and he ended up landing the airplane downwind. The pilot stated that the airplane touched down and he "immediately" applied the brakes to avoid colliding with a steel gate located at the end of the road. As the brakes were applied, the airplane drifted to the left and the airplane exited the roadway. Subsequently, the nose landing gear assembly collapsed, and the airplane nosed over and came to rest in the inverted position. Examination of the airplane by the owner revealed that both wing struts were bent, the vertical fin was crushed, and the wing spar sustained structural damage. At 0952, the winds at the Scholes Airport, near Galveston, Texas, located 14 nautical miles northwest of the accident site, were reported from 030 degrees at 11 knots. The pilot reported that the wind was from the northeast at 10 to 15 knots.