Hazard anticipation of young novice drivers - SWOV

impact on road safety. Despite the fact that to date for some illicit drugs no
clear negative effects on traffic safety have been found, it has been
demonstrated that combined substance use, especially the combination of
alcohol and illicit drugs, leads to an substantially higher crash rate
(Mathijssen & Houwing, 2005).
In contrast with drink driving, prevalence of illicit drug driving was
found the highest in the youngest age group of motorists (motorists between
18 and 24 years of age) in the Netherlands, but illicit drug driving was only
slightly less in the group of motorists aged 25-34 (Mathijssen & Houwing,
2005).
2.5.2. Fatigue
Fatigue has been defined as a state of reduced mental alertness that impairs
performance during a range of cognitive and psychomotor tasks, including
driving (Williamson, Feyer, & Friswell, 1996). The terms sleepiness and
drowsiness are often used as synonyms for the word fatigue, especially when
reference is made to the neurobiological processes that regulate the circadian
rhythm and the need to sleep (Dinges, 1995). Fatigue can be caused by time
on task and the complexity of the task, but also by lack of sleep. Lack of sleep
can be chronic when during a long period, the daily quality of sleep has been
poor and/or the daily quantity is not enough. Lack of sleep is acute when
task performance is impaired due to one bad and/or short night. Driver
fatigue can also occur when a person drives at moments when she or he is
normally asleep (e.g. nighttime driving). During a 24-hour cycle, the human
body has greater need for sleep at some moments (especially between
midnight and 4 a.m.) than on others. The 24-hour cycle of the body is called
the circadian rhythm. Finally, drowsiness, but not fatigue can occur when the
driving task is monotonous. This is sometimes called driving without
attention or highway hypnoses. Driver fatigue can cause crashes because of
deficits in attention, vigilance and information processing. When one falls
asleep behind the wheel, failure to perform the driving task is complete.
A recent naturalistic driving study that was called the '100-Car Naturalistic
Driving study', has revealed that drowsiness was a contributing factor in 13%
of the crashes and in 12% of the near crashes (Dingus et al., 2006). In a
naturalistic driving study, participants drive in instrumented cars.
Participants know that they are driving in instrumented vehicles, but these
instruments (e.g. cameras) are not visible or hardly visible and are
unobtrusive. In a naturalistic driving study, participants are not instructed to
use the car in a particular way. It is the intention to observe driving
behaviour in daily life. In the '100-Car Naturalistic driving study', car
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