I'm not entirely sure. There's a concept back home of the "filter in turn" system, where two roads meet that allows a constant flow of traffic. It's a lovely idea, that works well, even at the end of The Dual Carriageway or even entering The Tunnel. But why doesn't anyone implement this system for motorway lane closures?
Mind you the Highways Agency is based in London...
Filter in Turn
Mind you the Highways Agency is based in London...