HOURS OF DARKNESS INCREASE THE HAZARDS

Sportsmanlike Driving, 3rd Edition, 1955, The American Automobile Association

1. Fatigue or Drowsiness. Serious fatigue should disqualify a driver. As you work and exert your body, changes take place in the chemical makeup of your tissues. They collect "fatigue poisons." When sufficiently filled with fatigue poisons, you become drowsy and finally lose consciousness in sleep, even though you struggle against it.