Coming back up to Scotland from a day trip to sunny Blackpool. Mate driving, me in passenger seat. As you can imagine, doing it all in a day (early start, drive to Blackpool, Pleasure Beach for the day, drive back to Scotland) is pretty exhausting.
On motorway, night time. Mate doing 75ish. Luckily I had stayed awake. Became aware of car gradually and then quickly veering to left. Looked at mate. He'd fallen asleep. Needless to say I quickly (but as calmly as possible) wakened him up, then gave him a bit of a verbal ear-bashing!
I like to think if I'd been asleep the rumble strip at left inner lane would have wakened him up as the noise it makes is quite loud.