I read in a book about a marathon biker who deprived himself of sleep. He started waving at mailboxes thinking they were people. Then his follow crew forced him to stop when he was unable to stay out of traffic. He was hallucinating so badly he thought his crew were aleins. Read about it in Sleep Thieves.

A trucker in the desert fell asleep while driving and lost the road and went onto a salt flat where he drove 60 miles. He decided to go to sleep when he got out of his truck and realized he was lost. An airplane discovered him in the morning and had a highway trooper check it out.