On July 12, 1995, at 1047 hours Pacific daylight time, the pilot of an experimental Pitts S-1S, N715L, departed off the left side of runway 25R at Livermore Municipal Airport, Livermore, California. Visual meteorological conditions existed at the time. The winds were reported from 230 degrees at 7 knots. The aircraft sustained substantial damage and the pilot was not injured. The pilot departed an hour earlier for a local pleasure flight. According to the pilot, the aircraft began drifting to the left on rollout after a normal three-point landing. The aircraft did not respond to control inputs and the aircraft departed the runway. The aircraft proceeded parallel to the runway with the main landing gear wheels in a dirt furrow. The aircraft then collided with some tightly packed, heavy bales of hay from a recent mowing. The pilot reported to an Federal Aviation Administration inspector afterwards that there were no mechanical problems with the aircraft and that the aircraft got away from her.