On May 28, 1999, at 1250 central daylight time, an Air Tractor AT-502 agricultural airplane, N4533H, was substantially damaged following an abrupt maneuver to avoid a vehicle during takeoff from an airstrip near Cherry Valley, Arkansas. The instrument rated commercial pilot, sole occupant of the airplane, was not injured. The airplane was registered to Riddell Flying Service, Inc., of West Helena, Arkansas, and operated by Burnette Aviation, Inc., of Hickory Ridge, Arkansas. Visual meteorological conditions prevailed for the Title 14 CFR Part 137 aerial application flight for which a flight plan was not filed. The flight was originating at the time of the accident. The pilot reported to an FAA inspector and on the enclosed NTSB Form 6120.1/2, that he attempted to takeoff to the north from an elevated dirt airstrip which is also used as an access road. The pilot stated that the hopper was filled with a load of rice seed to be dispensed on a nearby field. The pilot further stated that the turbine powered tail wheel equipped airplane was also topped off with fuel prior to the accident flight. The pilot added that the takeoff ground roll for the airplane "had been much shorter on the 2 previous flights due to the lighter loads and the cooler temperatures." The 14,232-hour pilot reported that during the takeoff roll, soon after the tail wheel came off of the ground, he observed a white pickup entering the airstrip/road from a west cross-levee road. The driver of the pickup truck, who was the farmer whose fields were being seeded, had observed previous takeoffs but was not aware of how the airplane was loaded. As the airplane closed to within a few feet of the pickup truck, the pilot intentionally "pulled the aircraft off the strip to the east" in an attempt to avoid colliding with the truck and the driver. The pilot added that the airplane immediately stalled and fell into the rice field below the elevated road/strip. The airplane came to rest in a flooded rice field, approximately 25 yards short of the cross levee where the truck and the driver were sitting. Examination of the airplane by the owner and the operator revealed structural damage to the right wing and the empennage. The right main landing gear and the tail wheel were found separated from the airframe.