Two experiments were conducted to determine a level of control effort that can be exerted or exceeded by a high percentage of drivers. In both studies, female subjects were made to respond to an unexpected drastic increase in control effort while attempting maneuvers in a vehicle. In one investigation, test subjects were required to brake a vehicle in a dead-end pylon corridor, resulting in a 5th percentile pedal force capability for women of 100 lbs. In the other study, test subjects were required to perform a lane change maneuver, resulting in a 5th percentile steering wheel power capability for women of .023 horsepower. The results of these experiments are consistent with a recently published study (9) of maximum control effort in a static seating package.