Risk
Fatigue increases the crash chance
Fatigued drivers have a greater crash chance. Fatigue decreases the driving skills, leading to not keeping to their lane well and steering less smoothly. Drivers are also less capable of reacting alertly to, for example, speed reduction by drivers ahead or information from the surroundings. It also causes a bad mood and a reduction in motivation to drive safely: they become more quickly irritated, and are less inclined to keep to the speed limit or to stop at a red traffic light.
It is very awkward to precisely determine the influence of fatigue in causing crashes. This is because it is practically impossible to measure fatigue objectively, which is not so in the case of, for example, alcohol. However, various foreign studies maintain that fatigue is (partly) responsible for 10-15% of all severe crashes. If we assume that these percentages are not very different for the Netherlands, this means an annual number of 700-1000 severe (car) crashes.