Driving under the influence of alcohol is a common occurrence these days but driving when you are sleepy is equally dangerous.
Most people campaign against driving while intoxicated but there are very few who would talk you into being careful while driving when you might have a very good chance of falling asleep on the wheel.
It should be a conscious decision not to drive when you are too tired to or have been sleep deprived for a while since a driver who drives in such a condition very often loses his focus on the road and can end up not just hurting himself but also pedestrians as well as others on the road.