Lateral controllers for vehicles on automated highways are required to ensure small tracking errors even while providing a comfortable ride. In addition, they must be robust to changes in operating conditions and road-vehicle parameters. Sliding mode control has been successfully used to provide robust lateral control. However, such control usually has a high gain nature, often resulting in poor ride quality. The problems of tire and actuator saturation are also not addressed explicitly. This paper proposes the use of non-linear sliding surfaces for lateral control of road vehicles, to take advantage of the robustness of sliding mode control while avoiding the possible problems of ride discomfort and tire or actuator saturation. Simulation results are presented.