Motorists experienced major traffic chaos in Portadown as work began on the £1.5m improvement work on the Northway.
Tailbacks reaching across the town caused serious disruption this week as vehicles tried to negotiate the roadworks.
Work started on Wednesday on the 1.9km of carriageway from the Seagoe to Kernan Loop junctions.
It will result in the three current lanes increasing to four lanes.
Transport Minister Danny Kennedy announced the scheme. He said: “This is a significant investment in Portadown and involves a major road widening scheme which will result in a significant improvement to traffic progression on this critical link to and from the M1 motorway. With over 27,000 vehicles a day using the route the improvements will benefit not only the wider Craigavon area but also the many motorists travelling from the Armagh area.
“Initial work on a new drainage, vehicle restraint system, street lighting and vegetation removal has already started and should take up to eight weeks, weather depending.”
The Minister said: “Work on the main project will hopefully start during the summer, subject to the completion of the necessary land and contract processes. The work will last for approximately 14 weeks.”
As with all improvements of this type the planned dates are subject to favourable weather conditions. Roads Service said it will keep the public informed of any change.
A DRD spokesperson said: “Roads Service has carefully programmed the works operations and traffic management arrangements in order to minimise any inconvenience to the public.
“However motorists should be aware that some delays may be expected and that additional time should be allowed when planning any journeys in the area.”