Looks like an accident just a bit futher on from Monmouth tunnels headed south, both lanes on total stop, police cars gone through, but I m just the blind side of the bend to see whats happening.
Take a different route if you can .
it was chaos i drove through Monmouth to get to our yard.
One smaller truck had gone into the back of a articulated vehicle in the fast lane 
roads were closed both ways , although I didn’t see any sign of a smash on the other side of the carriage way, perhaps I missed it.
The surrounding roads were very heavy with traffic naturally with the diversion/ road closures.