On 2008-08-18, Tony Dragon wrote:
snip

All true except that northbound traffic has delays to get off the new
road & this is nothing to do with congestion further on.
You will see an increasing amount of traffic going north that is
starting to use the old road as it is often faster.


All that means is that delays propagate back from further North onto the
bypass. Then a relatively small number of vehicles will be able to get
to the junction faster if they use the old road. Then they cause extra
congestion at the junction. As more vehicles use the old road, they will
have to go slower, they will add to the congestion at the junction, and
the bypass will become faster again - but slower than it would be if
no-one used the old road.

E