The work, which will help improve journey times on the A14 near Cambridge, has seen a third lane added in both directions between junctions 31 and 32 as well as improvements to the westbound access roads to the M11 and A14 at the Girton interchange.
Construction started last April and was originally scheduled to finish at the end of March.
The new lanes have been open since April but overnight work to complete the improvements is taking longer than planned and is now expected to be completed early September.
Today, Highways England apologised for the delay and pledged to do everything possible to keep traffic flowing until the work is complete.
Highways England Service Delivery Team Leader Aran Nugent, said:
I appreciate this will be frustrating news for drivers, but I’d ask them to bear with us while we complete this important work.
We’re disappointed with these delays, and are working with our contractor, Costain and supervisor Amey, to understand why they have occurred and prevent similar issues happening in the future.
Our contractor made an error with the programming and there were added complications with diverting the communication cables alongside the road.
We want to provide a good service for road users and this is reflected in our contracts. It’s our responsibility to make sure that our contractors are performing well, and we will continue to work closely together to ensure that we fully understand and live up to these expectations.
We apologise for the delay and we are looking at ways to complete the work quicker such as using day time lane closures.
Work to replace lighting along this section of the A14 will be completed with the remaining work or rescheduled to be completed at a later date. A 50mph speed limit will remain in place for safety reasons, but we’re looking to see if it’s possible to remove this reduced speed limit.
The improvements on the A14 are part of Highways England’s £317m pinch point programme to improve more than 100 congestion hotspots nationwide. Prioritised in consultation with Local Enterprise Partnerships, they sped up delivery of road improvements with proven links to local development priorities. The A14 improvements will help to support the creation of 582 jobs and 1,480 new homes by 2020.
Members of the public should contact the Highways England customer contact centre on 0300 123 5000.
Journalists should contact the Highways England press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.