The invention relates to a driver-assistance system featuring fatigue detection, and a method for predicting a fatigue degree. The method for predicting an instant at which a predefined fatigue degree is expected to be reached in a vehicle system for fatigue detection, includes: (i) detecting the fatigue characteristic by continuously ascertaining the current fatigue degree of the vehicle operator; (ii) ascertaining a change in the fatigue degree over time within a predefinable time interval of the fatigue characteristic, and/or supplying an empirically determined change in fatigue degree over time; and (iii) ascertaining the instant at which a predefined fatigue degree is expected to be reached, based on the ascertained and/or supplied change in the fatigue degree.