Up to 50,000 motorists a day will be diverted along a two-lane carriageway for the duration of the works. The road will skirt the closed section of the bypass to allow workmen to excavate the tunnel.
Preliminary work is due to begin June 2013 while the temporary diversion route will come into effect from September. The project is expected to be completed by May next year.
The Borders Railway – running 35 miles (56.3km) between Edinburgh Waverley and Tweedbank – is set to be completed late next year, although the operation date has been set for summer 2015.
Assurances have been given that traffic disruption will be kept to a minimum during the works. It is understood that as yet no speed restrictions are planned along the route.
