per:
http://www.rospa.com/roadsafety/info...tigue_2011.pdf
Crashes caused by tired drivers are most likely to happen:
*on long journeys on monotonous roads, such as motorways
*between 2am and 6am
*between 2pm and 4pm (especially after eating, or taking even one alcoholic drink)
*after having less sleep than normal
*after drinking alcohol
*if taking medicines that cause drowsiness
*after long working hours or on journeys home after long shifts, especially night shifts
Drivers most at risk
Young male drivers, truck drivers, company car drivers and shift workers are most at risk of falling asleep while driving. However, any driver travelling long distances or when they are tired, is at risk of a sleep related accident.
I don't know if I'm cool with listing AC as "safety equipment" given the extenuating circumstances where it would make a difference and the impact to efficiency. I'm sure there is some safety benefit to having your windows open in even more situations too (can hear better anyway...).