On January 8, 2005, about 1505 mountain standard time, a Piper PA-28-161, N8351W, struck a taxiway location sign during landing rollout at Ryan Field Airport, Tucson, Arizona. International Aviation Training Academy was operating the airplane under the provisions of 14 CFR Part 91. The student pilot, the sole occupant, was not injured; the airplane sustained substantial damage. Visual meteorological conditions prevailed, and a flight plan had not been filed. The local instructional flight originated about 1400. In a written report, both the operator and the pilot reported that the airplane touched down abeam taxiway A4 on runway 24L. The pilot applied brake pressure, attempting to slow the airplane for a turn onto the adjacent taxiway. The pilot then decided to continue the landing rollout to the next taxiway and added power. As the airplane approached the taxiway, the pilot applied left rudder and the airplane responded by veering to the left. The pilot said he lost control, and the airplane overran the taxiway into the nearby grass. The pilot attempted to maneuver the airplane back to the taxiway, and the leading edge of the right wing collided with a taxiway location sign. The pilot reported no preimpact mechanical malfunctions or failures with the airplane.