When the Bedfordshire sub unit of the Eastern Road Construction Units was established its original design briefs included the M11 Cambridge Western Bypass, the A45 Cambridge Northern Bypass, the A45 Bury St Edmunds bypass and with a lowly priority the A45/A11 bypass of Newmarket. At that time the concept was perceived of a series of local bypasses on the A45. The emphasis to the west of Cambridge was on the improvement of the existing A45 towards St Neots.
The traffic work associated with the M11 and A45 in the Cambridge area however identified a strong demand for better northbound links with the A1 and the Sub Unit were given a brief to investigate the dualling of the A604 County Road between Cambridge and Huntingdon where Stirling Maynard and Partners on behalf of the then Ministry of Transport were developing proposals for a Huntingdon Bypass which would improve the connections to the A1 significantly. The A604 was already a problematic route for the local authority. Substantial commuter flows between Cambridge and Huntingdon caused peak hour delays which were exacerbated following the establishment of the new community of Bar Hill to the north of Cambridge.
Following Traffic Studies and a public consultation, the final decision identified the Green Corridor as the preferred corridor. Shortly afterwards the Bedfordshire Sub unit was appointed to undertake the identification and design of routes within the corridor.
Thus the final piece was put in place and the scene set for the implementation of a strategic trunk route linking the industrial Midlands to the East Coast ports.
The geometric standards have evolved, including those associated with the design of all forms of junctions, from at grade priority junctions to roundabouts and grade separated interchanges. In particular the operational aspects of weaving and merges and diverges are now better set out in the standards.
The applications of the design standards has resulted in a route which has similar characteristics along its length.
Apart from Newmarket and Cambridge Northern bypasses which were designed to Motorway design standards with provision for hardshoulders the rest of the route was designed to trunk road standards. The great majority of the length is a dual carriageway with full grade separation with a design speed of 120kph.
This west-east route, some 127 miles in length, forms part of the Ireland-UK-Benelux Link of the Trans-European Road Network. There are four distinct lengths of what is now the A14.