Abstract
Measurements of the directional response of an automobile to torque inputs applied at the steering wheel are compared with predictions yielded by a five-degree-of-freedom model of a four-wheeled, pneumatic tyred vehicle. This comparison demonstrates that the directional control and stability of the "free-control" automobile is satisfactorily characterized by the addition of a quasilinear representation of a steering system to a linear three-degree-of-freedom representation of the "fixed-control" automobile.