A friend of mine had an accident recently, being part of a 10-car pile-up on the M1 one Saturday morning. 

Impressively, given that all 10 cars were doing around 70mph when their panic-braking began, everybody walked away. No one was seriously hurt apart from the soreness of whiplash and some mild shock, although there was an awful lot of vehicle damage. 

My friend’s was car number three in the train of destruction, which was triggered by somebody undertaking and surprising the lead car, which my mate reckons may have been slow to react. 

But when its driver did brake it was hard enough to trigger his car’s emergency brake assist, prompting an older supermini without this feature to bury its nose beneath its tail, aided by the impact of my friend’s car hitting it too. My mate was hit by the car behind, and another seven cars followed that. Which was enough to close the motorway.