Work on a scheme to increase capacity and reduce delays on the A14 near Cambridge is due to start next week.

The project involves creating an additional lane in both directions between the Girton and Histon junctions, with access roads from the west-bound carriageway to the M11 and A14 also being improved.

Work begins on Monday and, subject to weather conditions, is expected to take about eight months to complete.

Two narrow lanes will normally remain available in each direction ? subject to a 50mph speed limit, enforced by average speed cameras ? but some overnight lane and road closures will be required, with traffic being diverted on to signposted diversion routes.

The work is part of a £317million “pinch point” improvement programme designed to boost local economies, reduce congestion and improve safety on the strategic road network in England, as outlined during the Chancellor’s Autumn Statement in November 2011.

Steve Davy, project sponsor for the scheme at the Highways Agency, said: “The pinch point programme provides smaller scale improvements that can deliver big returns by easing congestion and making journey times more reliable for road users, including hauliers and commuters to help boost local economies and drive economic growth.

“This scheme will significantly increase capacity, reducing journey time delays on the vital A14 and improving journey time reliability.

“The work has been very carefully planned to minimise disruption and that is why we are installing narrow lanes so we can keep two lanes of traffic moving at peak times, with lane and full road closures taking place overnight when traffic flows are lowest.”

The work to install the average speed cameras which will enforce the temporary 50mph speed limit, will take place over three nights, from Monday, April 14 , with lane closures between 8pm and 6am, in both directions. Eastbound the closures will be from the A428 Cambridge Road Bridge to the A14 junction 32 at Histon; westbound the lane closures will be from junction 32 to junction 31 Girton interchange. There will be associated narrowing of lanes on the slip road from the M11 at junction 14 on to the eastbound A14.

In order to install the narrow lanes, the westbound A14 will be closed overnight, between 8pm and 6am, for seven nights, from Tuesday 22 April between junctions 36 and 31, and continuing on the A428 to Madingley. Associated slip roads will also be closed.

The eastbound A14 will be closed overnight, between 8pm and 6am, for six nights from April 30 between junction 31 and 32. The eastbound A428 will be closed from Madingley to junction 31 of the A14, and the M11/A14 Junction 14 eastbound loop to eastbound A14 will also be closed during this six night period.

During the westbound A14 closures, traffic will be diverted via the A11, A505 and M11.Any traffic wishing to use the A428 will leave at M11 junction 13 Northbound, join the A1303 to Madingley then re-join the A428.

During the eastbound A14 closures traffic will be diverted via the M11 to junction 10, A505 and A11.

During the A428 closures traffic will be diverted via the A1303, M11 to junction 10, A505 and A11.