Assistance system against sleepiness

The present invention periodically performs an estimate calculation of a driver's degree of consciousness; and to that end it evaluates several physiological parameters (nodding, eyes shut, head position) to decide on the action on the vehicle according to the driver's condition. To that end it makes sure that the kind of road so allows it. The action is carried out gradually reducing the peak speed available in the vehicle, with each warning associated to a particular level of the degree of consciousness.