A section of the A6106 between Millerhill and the Sheriffhall roundabout will close for around six months from Monday.
This is so that it can be realigned to run parallel to the new Borders Railway, reopening again by the autumn.
The railway’s alignment cuts across the current road layout, meaning new roads are required to connect Millerhill to the roundabout.
To help relieve traffic pressure a new road and roundabout has been built to provide an alternative route between Millerhill and the Old Dalkeith Road (A7) via Shawfair.
Diversion signs will be put in place to direct drivers through the new layout.
The A6106 will be reopened by autumn 2014.
Read more in this week’s Advertiser, out now.