Incidence of near accidental drowsing in locomotive driving during a period of rotation.
The incidence of drowsings as a cause of near traffic accidents was studied on the basis of daily recordings or near accidental events by 288 locomotive drivers during a rotation period of 2-3 weeks. Of 198 near accidents reported during 2,290 trips, 34 cases, or 1,5 cases per 100 trips, were operation missess involving drowsing or strong drowsiness. Improper operation due to drowsing occurred at a certain rate for any group of drivers, irrespective of the type of train, running sections, weather, and other operative conditions such as train delays, whereas 117 cases of danger caused by unforeseen obstacles on the track were related to site characteristics, and 47 cases of other disorders were frequent in unusual operative conditions such as arrival-departure, poor signal display, wrong instructions, or equipment failure. Thus continued driving under ordinary track conditions at a more or less constant speed was likely to induce drowsiness under the dominant influences of fatigue and time of the day; 79% of such cases occurred between midnight and 6 a.m. Most drowsings on the second night appeared during the first 2-4 hr of duty. Effects of monotony and insufficient rest were discussed in relation to recurrent fluctuation in vigilance.
D000059:Accidents; D004782:Environmental Health; D006801:Humans; D009790:Occupations; D011890:Railroads; D012890:Sleep; D013223:Statistics as Topic; D013997:Time Factors; D014851:Wakefulness