194 A. Williamson et al.
Drivers who experienced high levels of sleepiness, higher likelihood of falling
asleep and of crashing were more likely to crash. Most significantly, for the aims of
this study, the results showed that drivers who rated the likelihood of falling asleep
in the next few minutes as very likely, likely or even possible were more than four
times more likely to crash. This shows that drivers are clearly aware of increasing
experiences relating to fatigue and sleepiness and are able to detect when these
experiences might lead to falling asleep. The fact that drivers are aware of these
changes makes it possible for them to respond earlier to avoid adverse road safety
consequences of crashing.
In order to find out how drivers were feeling ...