Vigilance under Highway Driving Conditions

Abstract

The effect of prolonged driving on the vigilance of Army truck drivers was srudied in cooperation with the American Association of State Highway Officials. A decrement in performance was predicted on the basis of long shifts, a highly repetitive cask, reported physical fatigue, and vehicle noise and vibration.Ss were 42 enlisted Army truck drivers (Men = 23 yr.). Ss drove large, heavily loaded commercial trucks repeatedly around experimental highway driving loops in 9-hr. shifts. One shifc consisted of 7 hr. of actual driving time sequenced in 6 driving periods of 90, 90, 90, 60, 45, and 30 min. Four 15-min. rest pauses and one 40-min. meal break were interspersed among driving periods. Ss monitored a visual discrimination task continuously during driving. Visual display units of 15 lights arranged in a circular fashion were mounted on truck dashboards. Signals appearing in 6 "critical" (red) panels were responded to by means of a foot pedal. Signals appearing in the 9 "noncritical" (white) panels were to be ignored. Critical signals were programmed at the rate of 30 per hour; inter-signal intervals ranging from 5 to 390 sec. occurred in random order. Non-critical signals appeared at the rate of 90 per hour. Signals were oP 1-sec. duration.The absolute level of vigilance was high. Critical signal detections aver---aged 83% for all driving periods combined. False detections averaged only 4% for all driving periods.There was no between-period performance decrement ( F = 1.21; df = 5/200; P > .25). N o measure of within-period decrement was possible. The absolute detection levels indicated, however, that any decrement that may have occurred within periods was relatively small.Individual differences in critical detection scores were wide (Range = 21 to 100%) and highly reliable (odd versus even driving periods, roc = .93; df = 40; P < .01). The range of individual scores became greater as the vigil progressed, resulting in a significant increase in inter-subject variance from --Driving period 1 to 6 ( t = 3.17; df = 41; P < .01).In view of past research, one possible explanation for the present lack of decrement is the relative complexity of the task. Performance decrements have been found repeatedly for simple (single signal source) vigilance tasks (Baker, 1959), but the evidence for decrement in complex (multiple signal source) vigilance tasks is scant (Frankmann & Adams, 1962 ). Also, the experimental task may have served as a stimulant co rather than a measure of vigilance performance.REFERENCES BAKER, C. H. Towards a theory of vigilance.

The Effects of a 48-Hour Period of Sustained Field Activity on Tank Crew Performance

“…These results corroborate informal coi,iments by officers and men that tank crews can efficiently perform their jobs during periods of 36 hours or longer without sleep, and ave often done so. The results also agree with the findings of previous investigations that performance efficiency may be sustained over relatively long periods of continuous activity (22,23,24,25).…”

“…Also important is the difference between the driving tasks used in this field test and those used by Drucker and others. A performance measurement that includes driving continuously for several hours or the manipulation of a simulator, as in Drucker's experiment, includes many characteristics of vigilance type of tasks in which performance is sensitive to the effects of extended activity (5,19,22). On the other hand, the specific tank driving measurement tasks used in this field test were periodic, of short duration, and presumably intoresting; they also demanded relatively simple unitary perceptualmotor response patterns.…”

Attention and Driving Skills in Aging and Alzheimer's Disease

“…Other studies have attempted to evaluate vigilance during driving by imposing a secondary task requiring detection of infrequent signals (Boadle, 1976;Brown, Simmonds, and Tickner, 1967;Dobbins, Tiedemann, and Skordahl, 1963;Ellingstad and Heimstra, 1970;Heimstra, 1970). None of these studies found significant evidence of effects of the time spent driving (from 2 to 12 h) on the accuracy or speed of detection of secondary task signals.…”

The efficacy of some auditory–vocal subsidiary tasks as measures of the mental load on male and female drivers

“…(c) Attention Brown (1965 b), Brown and Poulton (1961), Brown et al (1967), Dobbins et al (1963), and Summala and Naatanen (1974) have all used tasks of attention in various forms, involving various types of memory load (see table 1). The task used in this experiment was intended to reduce the memory component to a minimum.…”