Monotony of road environment and driver fatigue: a simulator study

1. Accident Analysis and Prevention 35 (2003) 381-391 Monotony of road environment and driver fatigue: a simulator study Speaker: Jenny 2008/10/22 Pierre Thiffault, Jacques BergeronLaboratoire de Simulation de Conduite, Center de Recherche sur les Transports, Universite’ de Montre’al

2. Agenda • Purpose • Literature Review • Causes of fatigue and drowsy driving • Task induced fatigue: the impact of monotony • Method • Results • Discussion

3. Purpose • Drowsiness and hypovigilance frequently occur during highway driving, and it would cause accident. • To evaluate the impact of monotony of road environment on driver fatigue.

4. Causes of fatigue and drowsy driving • Long hours, time of day and sleep-related problems are major contributors to fatigue. (Smiley, 1998) • sleep-related accidents (Pack et al., 1995) • 2:00 – 6:00 a.m. • 2:00 – 4:00 p.m. • Endogenous and exogenous factors to influence the physiological states that under lie alertness and vigilance. (Cabon et al., 1996; Thiffault and Bergeron, 1997)

5. Causes of fatigue and drowsy driving • The highway design lacks stimulation, which results in fatigue-related accidents. (Nelson, 1997) • Should teach how environment conditions influence the development of fatigue symptoms.

6. Task induced fatigue:the impact of monotony • The risk of falling asleep is higher on straight, monotonous roads in situations of low traffic, where boredom is likely to occur. (Sagberg, 1999) • Sleep was involved in 23% of accidents occurring on monotonous motorways. (Horne and Reyner, 1995)

7. Task induced fatigue:the impact of monotony • It could be beneficial to integrate novelty and variety into the drivers task and environment. (Brown, 1991) • Visual stimulation can be used as countermeasures to combat driver fatigue. (Moses, 1995) • Monotony: stimulation’s nature, quantity or variation (Wertheim, 1991)

8. Method • 56 male university students (age: 24) • Material: University Simulator • Simulated highways: actual Canadian geometric route design standards • Likert scale: subjective level of alertness (SA) • Road A: repetitive scenery • Road B: rare random trees, houses and farms, and occasional pedestrians • A bridge cross a large river

9. Experiment • Post-lunch dip period • 13:00 arrive • 13:20~13:25 practice operating the simulator • 13:25~13:30 SA test • 13:30~13:10 driving (40-min) • 14:10~14:25 Take a break + SA test • 14:25~15:05 driving • 15:10 SA test

10. Measurement of fatigue • Standard deviation of lateral position (x) • Mean amplitude of steering wheel movement • frequency of steering wheel movement

11. Results • ANOVA • Steering wheel movement variable • 8 blocks (5- min) • Time on task effect • The effect of monotony

12. Results • SWM of road A is larger than road B, but the difference is not significant. (p< 0.391)

13. Results

14. Results

15. Discussion • Both roads lack vehicles, curves or hills. • Fatigue peak: 20-25 min

16. The physiological and psychological process underlying the fatigue phenomena show that different classes of factors may affect alertness at any given point in time during driving.