1. A system for estimating a driving intention of an operator of a vehicle comprising: an information detector that detects information necessary to operate the vehicle; an operational input detection device for detecting an operational input by the operator; first and second imaginary driver operational input calculation devices configured to respectively calculate imaginary operational inputs of multiple imaginary drivers, wherein the first and second imaginary driver operational input calculation devices incorporate different methods for formulating the multiple imaginary drivers and calculating the imaginary operational inputs, each of the multiple imaginary drivers representing a reference model target position of the vehicle different from its current position and a respective imaginary operational input associated with an action needed by that imaginary driver to attain its respective reference model target position of the vehicle; an imaginary driver operational input selection device configured to select one of the multiple imaginary drivers based on the imaginary operational inputs calculated by the first and second imaginary driver operational input calculation devices; and a driving intention estimator configured to estimate an intention of the operator based on the operational input of the operator detected by the operational input detection device and the one of the multiple imaginary drivers selected by the imaginary driver operational input selection device.