Chiswick Flyover is situated at the end of the M4, joining the motorway to the A4, a main arterial route carrying thousands of vehicles into Central London each day.

M4 junctions 5-7 is a composite pavement with the construction being made up of 190mm of wet-mix at the base overlaid with 140mm of bituminous surfacing.

The A55 North Wales from Chester to Caernarvon is a very busy trunk road, which takes a constant stream of heavy goods vehicles to and from the sea port of Holyhead, as well as local and industrial traffic. At weekends and during the summer months, the A55 also carries a considerable amount of holiday traffic making for the Welsh coast.