Carillion can now start work repairing the A58 Woodhouse Tunnel, which is suffering severe concrete damage and deterioration from extensive chloride attack caused by winter de-icing salts.
The damage is so severe that the structural capacity of components is now being affected.
The scheme is the last of three large highway structures needing maintenance on the Leeds Inner Ring Road, while a longer term strategy is developed.
If the work was not carried out sections of the IRR would have had to closed to maintain public safety.
The remaining works to the Woodhouse Tunnel are scheduled to start later this month with completion in March 2016.
The long timescale is because the works can only be undertaken during a large number of short closures of the road if significant delay to traffic on this vital route in Leeds is to be avoided.
