The A5117 Deeside Park Junctions Improvement scheme near the end of the M56 was officially opened on the border of Cheshire and North Wales today.
A new three mile road cuts out the congestion at the A550, A540 and M56 junctions.
Andrew Adonis, transport minister, said: "The Government is committed to tackling congestion and improving safety so I am delighted that improvements to this historic gateway have now been completed.
"Road users are already seeing the benefits of removing three bottleneck junctions. As well as reducing delays and improving road safety, the improvements will help boost economic regeneration by improving access between England and Wales."
The Welsh Assembly Government contributed £4.7m towards the scheme while the European Union gave £3.6m because the route forms part of the Trans European Route Network.
The Highways Agency planted 70,000 native trees and shrubs including willow, birch, ash and poplar along the road. In addition the scheme will create 110,000 square metres of wildflower meadow, 11 new ponds and a large wildlife wetland area.
The scheme took nearly three years to complete.