A £200,000 study to establish if a flyover or underpass should be constructed at a heavily-congested roundabout is to be launched.
Engineers will start investigating from next month whether the steps could be suitable for the busy Sheriffhall junction, near Dalkeith, which is plagued by rush-hour tailbacks.
Transport Scotland yesterday awarded the lucrative six-figure contract to consultants URS Infrastructure and Environment Ltd to complete the feasibility work.
The project is due to be finished within seven months.
Edinburgh, East Lothian and Midlothian councils have all welcomed the investigation into Sheriffhall, having previously argued the chaotic intersection is holding up housing and transport developments in Edinburgh’s south-east.
Proposed housing developments at Craigmillar and Shawfair, along with a potential tram route to Dalkeith, also hinge on the improvements.
East Lothian Council transport spokesman councillor Michael Veitch said: “We feel this work is long overdue. We are particularly keen that East Lothian benefits from future investment in upgrading and improving transport links, which are vital to the county’s economy.
“I really hope that this work at Sheriffhall will bear fruit and that any recommendations for upgrading works are actioned swiftly.’
Edinburgh planning convener councillor Ian Perry said last month that Sheriffhall was already “near capacity”.
The notorious roundabout has made name-and-shame lists of the UK’s worst road junctions in recent years. In 2009, it came ninth in a top ten that included Birmingham’s Spaghetti Junction.
An estimated 60,000 cars use the roundabout each day.
Transport Minister Keith Brown said: “Sheriffhall roundabout is the only junction on this key road that does not have a flyover junction, leading to lengthy tailbacks, especially at rush hour.
“The purpose of this initial work is to look at possible junction improvement options and to get a better understanding of the difficult ground conditions in the area.”
Transport officials said Sheriffhall posed a challenging location with a geological fault running through the roundabout and mines in the area.
Green Party Councillor Ian Baxter said segregated laneways for cyclists must be included in any potential overhaul.
He said: “Any improvements to Sheriffhall are certainly welcome, but they must include safe and preferably segregated provision for cyclists travelling between Edinburgh and Midlothian.
“This is a notoriously dangerous black spot for cyclists and if the Scottish Government is really committed to speeding up journeys on key roads, encouraging people to commute by cycling must be an integral part of that.”