Abstract
Driver control movements were studied in two simple steering tasks: driving along a straight lane and on a circular path. In both cases drivers were found to make most of their control movements within a fairly small frequency range. An attempt is made to explain these results in terms of the information being used by the driver to steer the car. In the circular-course experiment each driver drove the vehicle with three different steering ratios. Change of steering ratio did not show any consistent effect on the form of the spectrum of steering-wheel angle.