On Fri, 02 Aug 2019 21:52:12 +0100, Harry Bloomfield, Esq.
wrote:

Ian Jackson presented the following explanation :
I don't like queues, do you?

No, but I can cope with them without becoming too upset.

When the traffic merges well before it
absolutely has to, there's a far better chance of it being able to maintain
speed, and no queue forms. If left until it has to merge, there is more
chance a bottleneck occurring, and everything grinding to a halt. And as I
said, I don't like queues!

The merge happens at full speed with a little cooperation and everyone
behaving at the point where it has to merge.

Until it doesn't. Until someone misjudges it and it all ends in tears.
That's why they get you to do it far away from the problem and 'most
people' do just that.

If everyone merges early, it is too much of a temptation for someone to
not go steaming down the outside lane, to bully there way in.

Quite, but not the same issue as the merging at speed one.

That
causes things to grind to a halt, whilst extra space is made for the
intruder.

Or not ... when they are up inside some HGV who isn't going to be
bullied.

Cheers, T i m