The effects of steering ratio and force feedback on driver- vehicle closed loop control performance are quantified through the use of maximum likelihood parameter identification methods. Responses of vehicle and driver to simulated wind gust disturbances in lane regulation tasks are used in post-experiment identification of vehicle and driver model parameters. A vehicle specially equipped with hydraulic servos is used to simulate a wide range of steering ratio and stiffness, with all other vehicle parameters held constant. Coefficients in the driver model are shown to be influenced by changes in the steering system parameters; these effects are discussed in terms of fixed and free strategies for driver control.