Psychophysiological changes during long-distance driving may be associated with driving fatigue and morbidity. Measures of stress and arousal, including heart rate, blood pressure, catecholamines, cortisol, state anxiety, and self-ratings of stress and arousal were collected from 10 long-distance bus drivers during 12-hour driving shifts and at matched times on nondriving rest days. Cardiovascular and catecholamine data were elevated across the entire work day, compared with rest days. Self-reported stress and state anxiety were elevated only at the preshift measure, and these elevations were interpreted as the result of anticipatory anxiety and additional work demands at the beginning of the shift. Decelerating activation from the 9th to the 12th hours of driving were reflected in slower heart rate and lower subjective arousal ratings. Suggested explanations for these findings are that drivers experience a release of tension when they anticipate the end of the shift and therefore deactivation is a signal or precursor to the onset of fatigue in physiological adjustment mechanisms.