The pilot reported that the landing, in variable and gusty wind conditions, was uneventful. During the landing roll he aligned the airplane with the left edge of the runway to facilitate a left turn onto taxiway “K.” He slowly started the 120-degree left turn; however, the airplane would not straighten despite right rudder or brake input. The airplane continued to turn left until it exited the taxiway, rolled onto the grass, and impacted a taxiway sign. Postaccident examination of the airplane’s brake system did not reveal any anomalies that would have precluded normal operations.

At the time of the accident, the AUS METAR indicated wind was from 040 at 7 knots. In addition, it reported that the wind direction varied between 250-140 degrees during the previous hour which is consistent with the potential for windshear