Monotony of road environment and driver fatigue: a simulator study Anil Divvela Kenny Stauffer

The objective of this study was to evaluate the impact of the monotony of a road environment on driver fatigue Purpose

Previous Research Sleep related accidents may account for at least 40% of fatal accidents (Desmond & Matthews, 1996). Risk of falling asleep is higher on straight, monotonous roads in situation of low traffic (Sagberg, 1999) A situation is said to be monotonous is when stimuli remain unchanged or changing in a predictable manner (McBain, 1970)

The Theory is there is a link between monotony of road environments and driver fatigue. Theoretical Basis

Applicability-practical Contribution The contribution would be to prevent future car accidents by understanding the link between driver fatigue and monotony. This might lead to design changes in cars to help drivers stay awake. Or inform them of impaired driving patterns. Highway designers could also build roads that increase visual stimulation.

Theoretical Contribution The theoretical contribution is understanding how monotony effects drivers. How fatigue and monotony of road conditions correlate with the number of accidents.

Methodology Fifty-six male university students participated in two simulator studies There was a fifteen minute break between studies to diminish fatigue effect from the first study.

Data Collection Variables –Steering Wheel Movement (SWM) Larger steering wheel movements are needed to correct larger lane deviations. –Standard Deviation of Lateral Position (SDLP) Deviations from the center of the lane. –Standard Deviation of Steering Wheel Movement (SDSWM) Shows the extremes of the larger steering wheel movements.

Statistical Analysis The SWM mean amplitude increase over time is significant because it indicates there was a an effect of fatigue on steering behavior.

Statistical Analysis There was significant results for the frequency of the steering wheel movements. SWM (from 1° to 5°) decreases with time (P<0.001). SWM (from 6° to 10°) increases with time (P<0.001).

Conclusions No significantly different results of SWM amplitude or SDSWM for road A and road B.

Conclusions (cont.) The frequency of large steering wheel movements were more prevalent when driving on road A than road B (P<0.001). Interaction effect between time and monotony factors is marginal (P<0.062).

Future Research Evaluate the impact of interruptions of monotony that are more pronounced. Factors such as size, color, intensity, shape and content of the visual stimulation are dimensions that should be targeted.

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