A Pilot Experiment on Driver Task Performance with Fixed and Variable Steering Ratio

The experimental program described here was conducted in order to determine the effect of fixed and variable steering gear ratio on driver task performance. Three fixed gearbox ratios and two variable ratios of the Bendix Varamatic type were tested, using a single vehicle. Four steady turn driving tasks were used, each producing the same lateral “g” (0.2g) and a transient maneuver task, induced by applying a step change in front wheel angle to the vehicle, was also used. The pool of test subjects consisted of student drivers with an average of 39 hr of on-the-road driving experience.