Highways Agency Project Manager, Mark Saunders, said:
We have worked hard to get the new roundabout layout open to traffic in time for the Easter holidays.
The A1 Black Cat opened to traffic last week and the traffic signals are now fully operational.
We will remain on site to check the traffic signals are working with the flow of traffic.
Drivers should notice a difference to their journeys now as the opening of the new roundabout was an important step in finishing work on the project.
There is still some finishing off works which will be completed using overnight closures and scheme completion could be late April.
Members of the public should contact the Information Line on 0300 123 5000.
Journalists should contact the press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.