1. A system for estimating a driver intention comprising: an information detector that detects information necessary to operate a vehicle; an operational input detection device for detecting an operational input by a real driver; 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 calculate the imaginary operational inputs of the multiple imaginary drivers based on different methods or different information; an imaginary driver operational input selection device configured to select one of the multiple imaginary drivers based on the imaginary operation 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 real driver based on the operational input of the real driver detected by the operational input detection device and the one of the multiple imaginary drivers, selected by the imaginary driver operational input selection device.