The authors analysed experimentally the driver's behaviour and vehicle responses as a closed loop system, for the cases of running against crosswind gust and lane change driving in both ordinary and emergency conditions, and the following three phases of driver's behaviour are observed as common nature: (1) Lag of steering or non-steering period; (2) Instinctive and programming steer by driver's experiences; (3) Correcting and adjusting steer as a tracking motion for the desired path. From the experimental analyses and computer simulations, the following conclusions are obtained: (1) Crosswind sensitivity coefficient in the case of fixed control is also useful to evaluate the responses of vehicle-driver system against crosswind gust in most cases; (2) The system becomes unstable, when the external disturbance exceeds the driver's ability and the dynamical characteristics of a vehicle in low speed, and when the dynamical stability of a vehicle is lost by improper steering in high speed.
Abstract