Highways England says the scheme at Posthouse Roundabout where the A55 meets the A483 near Chester will be fully open for commuter traffic on Monday morning.
In the meantime, drivers are being advised that the roundabout will be affected by partial daytime and full overnight closures from 8pm on Friday 26 June until 5am on Monday 29 June while contractors work to complete the scheme.
The overnight closures will include all the western side of the roundabout and the northbound A483 from the Pulford traffic lights on Friday and Saturday night, together with the eastern side of the roundabout and the southbound approach from the A483 on Sunday night.
During the day on Sunday, the western bridge on the roundabout will initially be closed followed by a closure of the eastern bridge.
One lane will remain open in both directions on the A483, and on the westbound entry slip road and eastbound exit slip road from the A55. The other slip roads will be unaffected by the work.
The scheme will deliver jobs and growth to the economy with over 11,500 jobs in the wider area by 2020 and a further 3,750 jobs beyond 2020.
Bob Baldwin, Highways England’s North West Delivery Team Leader, said:
The closures put in place last weekend enabled us to make good progress with the work and regular users of this busy junction will now see it taking shape. To ensure that we are able to have the roundabout operational for peak-time traffic on Monday morning, additional closures are required this weekend.
We apologise for the continued delay and disruption in completing this complicated improvement scheme and for the inconvenience these delays have caused to road users on both sides of the border. We have pulled out all the stops and the end is now in sight.
We would like to thank road users for their continued patience and hope they will appreciate more reliable journeys through the junction and the longer term benefits such as investment in jobs and housing these improvements will bring.
We have tried to keep traffic moving during the day on the A483 by keeping one lane open onto the roundabout but drivers travelling from the A483 onto the A55 may have to follow clearly-signed diversion routes.
Diversions will be in place over the weekend closures and drivers are being encouraged not to use the roundabout unless it is absolutely necessary.
Road users are being advised to leave extra time for their journeys with delays at peak times likely.
The junction improvement was made in response to concerns about the impact of congestion on commuters and business investment – with agencies on both sides of the border including the Welsh Assembly Government, Cheshire and Warrington Local Enterprise Partnership and Flintshire County Council supporting the initiative.
By increasing capacity on the roundabout and slip roads, and improving the flow of traffic on the A483 south of the roundabout, peak-time journeys through the junction are expected to drop to almost off-peak journey times.
Full details of road closures are on the Highways England website at: www.highways.gov.uk/roads/road-projects/A55A483-Improvements.
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.