 Previously (since the A2 Canterbury bypass was constructed in the early 1980s), the two slip roads at Thanington were east-facing and led only to and from Dover.In 2006, the Government, the Highways Agency, Kent County Council and Canterbury City Council agreed that adding the two west-facing slip-roads would help to ease the traffic congestion in Wincheap between the Westgate and the A2.The fourth slip-road is still awaiting funding and construction.