I go with cold air in the face and sometimes sing (but only when alone). Just got back after a 3 hour drive home from Vermont. I'd much rather do the drive in the morning than late at night. So I'll often spend a night somewhere rather than drive late at night. I've never fallen asleep driving, and I don't use caffeine. But I once fell asleep on my bike. I did not crash but woke up to find that I was heading straight for a concrete bench.