Ladybirder, are we to take it that you don't drive in central London ? Your counsel of perfection is utterly impractical, which is a reason why this King's Road junction makes so much money. If all drivers waited for the road, into which they are intending to turn, to be completely clear for at least a car's length, before entering the box, traffic would be gridlocked. Every driver has to trust that the intended road's traffic will move on a little before he needs to enter it. If he is caught out, and he leaves even a foot of vehicle overhanging the box, the Council collects.