As people are talking of fatigue affecting performance and the associated regulations both in the US and EU, I thought I would refer to research that has been done using driving simulators. There is a lot of this research so just one link for now, it really merits its own thread perhaps in Tech Log.
from
How do prolonged wakefulness and alcohol com... [Accid Anal Prev. 2001] - PubMed - NCBI
How do prolonged wakefulness and alcohol compare in the decrements they produce on a simulated driving task?
" Alcohol consumption produced changes in speed deviation and off-road occurrences of greater magnitude than the corresponding levels of prolonged wakefulness. While limited to situations in which there is no other traffic present, the findings suggest that impairments in simulated driving are evident even at relatively modest blood alcohol levels, and that
wakefulness prolonged by as little as 3 h can produce decrements in the ability to maintain speed and road position as serious as those found at the legal limits of alcohol consumption."