A fatigue alarm system and method for an automotive vehicle driver is adapted to measure periods of time during which the vehicle is driven and to subtract therefrom periods of time during which the driver rests. The driver rest periods are distinguished from brief stops of the vehicle in order to accurately measure the adjusted period of driving time. In order to distinguish rest periods from brief traffic stops, the duration of vehicle stops are measured and compared with a given value. When the vehicle stop periods are shorter than the given value, the vehicle is judged to be stopped briefly, i.e. that the driver is not resting, and the measured driving period is incremented by the measured vehicle stop period. On the other hand, when the stop periods are longer than the given value, the driver is judged to be resting. In this case, the measured stop time is subtracted from the measured driving time after being adjusted by a suitable proportionality factor. The result of measurement is visually displayed by means of a plurality of fatigue level indicator segments. The threshold levels at which each indicator segment is activated or deactivated in adjusted in accordance with its current activation state in order to avoid hunting thereof.