There is a restriction on 'JCBs' and the like using the Newcastle/Gateshead Western Bypass during 'commuting hours' (I forget the details).
This was done because of the inevitable delays that ensued each day as these contractors used the by-pass to travel to and from their place of work -usually when everyone else was doing the same (as well as the A1 traffic of course).
Edited to add:-
http://www.honestjohn.co.uk/forum/po...14845&m=150433