HUMAN VIGILANCE IN RAILWAY AND LONG-HAUL FLIGHT OPERATION

Human operators in transport operations are often confronted with mono tony, boredom, and irregular work schedules. This situation has become increasingly more acute because of the growing automation of systems. This paper presents methodology and preliminary results for two field studies on the vigilance of train drivers and long-range aircrews. Th e aim of these studies was to identify factors that can modify vigilan ce and to elaborate several specific solutions for reactivation. The m ethod is based on the collection of physiological data in the field an d on task observation of the operators. The recorded physiological dat a (EEG, EOG, EKG) permit an evaluation of vigilance and mental workloa d. The rest-activity cycles are estimated by actometry. The use of EEG and EOG are discussed in relation to monotony and sleep deprivation. For pilots, results show a high occurrence of decreased vigilance, par ticularly during phases of low workload (i.e., when cruising). Further more, it was shown that these periods of lowered vigilance can occur a t the same time for two crew members. A great number of incidents of d ecreased vigilance were also observed for the train drivers. These inc idents occurred even though the operators sometimes had high levels of activity. A direct relation was also noted between sleep duration and the onset of rest. These studies provide several means for maintainin g vigilance during activities and improving the system of work schedul e rotation.