Abstract: An apparatus for estimating a vehicle maneuvering state and controlling a vehicle running characteristic includes a controller having a fuzzy estimating function and a neural network function. The controller carries out frequency analysis on vehicle driving parameters such as vehicle speed, steering angle, opening degree of an accelerator, and longitudinal acceleration and lateral acceleration of a vehicle, to thereby determine a mean value and variance of each parameter. It implements fuzzy inference based on a traveling time ratio, an average speed, and an average lateral acceleration, which are obtained from vehicle speed and/or steering angle, to thereby calculate road traffic condition parameters, including a city area degree, a jammed road degree, and a mountainous road degree.