In message , at 17:54:39 on Wed, 19 Jun
2019, tim... remarked:

[route for the M25]

The only disruption will come at the end, when the traffic is
diverted to the new route. My guess is that the northbound traffic
will be moved first, with a few weeks of lane 1 closures required
while they connect the new to the old carriageways, then an
overnight closure for the final switch to be made. The same
procedure would then be followed a few months later to divert the
southbound carriageway to the new alignment.

The amount of work you would be expecting them to do "overnight" beggars
belief.

I disagree.

Build the two new carriageways. At each end, cut them off very close to
the edge of northbound lane 1 (there's no hard shoulder, right? if there
is, adjust description accordingly).

Cone off northbound lane 1. Spend a week or two filling in the narrow
gap between the old and new northbounds at each end.

Not sure that you even need a closure to switch over. Simply move all
the cones.

Repeat for the southbound (though this time you're closing lane 4).

Yes, that's what I'm expecting.

I have never in my life seen construction companies do this

For once I agree with Tim.

While it's not quite the M25, the A14 is one of the busiest dual
carriageways in the country.

They've recently finished (ahead of schedule) building the green-fields
bypass round the southwest of Huntingdon, and now just need to splice it
onto the old road towards Cambridge and the M11.

Plenty of opportunity to stagger this, achieve it by some crafty
re-arrangement of bollards etc.

But no. They've closed the road from 9pm yesterday until 5am on Monday.

ps The competition now is to see how long the new road takes to get on
various mapping sites, satnavs etc. Tom Tom's doing the best, fsvo,
with not just the road but as I type a 3.5mile eastbound queue on it
before it's even open. Contractors vehicles, the speculation is.
--
Roland Perry