Highways England says work on the £1.5billion A14 upgrade remains on course to begin “by the end of 2016”.
And officials are confident that, subject to planning approval from the Government, the upgraded route will be open to traffic by 2020, "on time and to budget".
The announcement, made on Monday, came as Balfour Beatty Carillion was unveiled as the contractor for the third construction phase of the project, which will see widening of the existing A14 from Swavesey to Milton, near Cambridge.
Chris Taylor, director for complex infrastructure at Highways England, said: "This award is another step closer to our commitment to deliver the A14 Cambridge to Huntingdon improvement scheme. Now all three joint-venture contractors are on-board, they will work collaboratively to finalise the pre-construction planning, to deliver the excellence that our customers and stakeholders expect of us.
"While we appreciate our planning application is yet to be fully examined by the Planning Inspectorate and we are yet to receive permission to start construction, this third appointment will add to the support we need to prepare for works getting underway on time and to budget."
Last week, the Planning Inspectorate held a final round of consultations with stakeholders, including the Brampton A14 Group and Hilton Parish Council, regarding noise, traffic and design associated with the proposal.
The issues raised will now be considered by inspectors before a report is finalised in November and a decision is made by the Government as to whether the A14 upgrade can go ahead around May next year.
Peter Balicki, chairman of Hilton Parish Council, said: "The hearings with the Planning Inspectorate were well attended, there were representatives from parish councils and action groups, and we put across the message that we would still like Highways England to improve the mitigation.
"As a parish council we will continue to push for as much mitigation as we can get in terms of noise and air pollution."
In June, the detailed design contract was awarded to Atkins CH2M joint venture at a total cost of £35.3m. Costain Skanska joint venture were awarded construction package one, covering the A1 at Alconbury to the East Coast Mainline, and package two, covering east of the East Coast Mainline to Swavesey.
The value of the pre-construction phase was £1m. Subject to the scheme being given the go ahead, the joint venture will deliver £598m of construction work.
The fourth package is for the demolition of the viaduct over the East Coast Mainline at Huntingdon and associated works - this will be awarded in 2019.
The proposed improvement scheme will involve a new major bypass between Swavesey and Brampton, widening the A1 between Brampton and Alconbury, widening the existing A14 between Swavesey and Milton, improving the junctions at Bar Hill, Swavesey, Girton, Histon and Milton, Huntingdon town centre improvements, to include the demolition of the viaduct, and a new local access road.
The planning application was submitted to the Planning Inspectorate in December 2014.