The interchange near Didcot is set to become become a ‘hamburger’ style roundabout, characterised by a carriageway through its centre.
Up to six shortlisted firms will be invited to submit tenders in April for the Government pinch point scheme.
The winning contractor will need to build a new structure under the A34 for the hamburger link road.
This will be constructed within the existing A34 embankment and will be a single span bridge with a precast concrete Y beam and in-situ concrete slab deck.
Improvements will support the development of new employment opportunities in the Science Vale UK Enterprise Zone and new housing in the Didcot, Wantage and Grove areas.