My thoughts are with the families, If I’d have stayed in Cornwall for the extra night that I was considering I’d have been passing that junction at about the time it happened!
That stretch of motorway seems to be an accident blackspot, several times I’ve been held up around Bridgewater, one time I ended up having to divert adding 4hrs to my journey home.
It’s also worth noting that Bridgewater had flash flooding yesterday, that amount of water, heavy rain (it seems to be raining there more than anywhere else on the m40/A30, it’s bit of a micro climate there) and thick fog, couple that with folk who will have been driving for around 2hrs+ coming up from the south. Its a worry given I drive that route a hell of a lot.