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

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

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.

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)

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.

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)

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)

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

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

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

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

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

Results

Discussion Both roads lack vehicles, curves or hills. Fatigue peak: min

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.