1. A method for continuously monitoring the gaze direction of a driver of a vehicle over time, said method comprising: receiving video captured by a camera within a vehicle, said camera mounted facing a driver of said vehicle; extracting frames from said video; detecting a facial region corresponding to a face of said driver within said extracted frames; computing feature descriptors from said facial region; and applying a gaze classifier with respect to said vehicle, said driver, and said camera, wherein said gaze classifier receives said feature descriptors as inputs and outputs at least one label corresponding to at least one of a predefined finite number of common driving gaze directions to identify a gaze direction of said driver of said vehicle.