The new road which links the A5 with the M1 via the new 11A junction will open to traffic tomorrow morning.
The 2.8 mile dual carriageway, which will be open by 6am, will become part of the A5.
The new M1 junction 11A, which will connect the new road and the new Woodside Link road to the M1, will also open at the same time.
The scheme includes two other new junctions and six new bridges.
The lane restrictions on the M1 which were in place during the construction of the new road will be restored to full capacity.
The national speed limit will apply on the new, dualled section of the A5.
Drivers are asked to take extra care as the road layout has changed with the introduction of new slip roads and the new junction.
The new road replaces a section of the A5 through Dunstable which is being handed over to Central Bedfordshire Council and Hertfordshire County Council.
Some minor work including the completion of new sign installation will need to take place after the new road is opened and the old section handed over to the council Single lanes will be closed for this to be done.