The new Raith Interchange underpass is set to open to traffic after three years of major works.
Roadworks have been underway at the motorway junction for the last three years as part of a huge improvements project on Scotland's motorways.
Cabinet secretary for the economy Keith Brown announced the Raith Underpass will fully open to motorists on Thursday.
The "complex and challenging" construction programme will "dramatically improve the heavily congested junction" near Hamilton in South Lanarkshire.
The new A725 underpass which runs below the M74 motorway will open to traffic for the first time in the early hours of Thursday.
Fifty years on since Raith Junction in South Lanarkshire first opened to traffic, the video and fly-through gives road users a first glimpse inside the underpass ahead of its opening to traffic.
The Scottish Roads Partnership (SRP) began construction of the £500m M8 M73 M74 Motorway Improvements Project on behalf of Transport Scotland in February 2014.
Upgrades were first made to the A8 between Glasgow and Edinburgh to complete the "missing link" then major improvements got underway on the M73, M74, and A725 and the junctions which connect the three routes - the most significant of which is Raith.
Keith Brown, said: "The opening of the new underpass at Raith is a major and significant milestone in this massive transport infrastructure project.
"The Scottish Government is investing almost half a billion pounds to improve central Scotland's road network.
"This investment will make a tangible difference to road users, alleviating the traffic congestion that has been a historic problem at Raith, and improving journey times through the junction by up to 15 minutes.
"The new underpass, and the strategic road network to which it links, will be a considerable benefit to commuters and businesses right across Scotland."
Graeme Reid, project manager for the M8 M73 M74 Motorway Improvements Project, said: "The creation of the Raith underpass and the surrounding local roads network has been the most technically complex and challenging part of the project.
"Not only has SRP had to keep the traffic moving through the junction whilst carrying out this major feat of engineering, they have had to overcome a significant technical challenge - the high groundwater caused by the junction's close proximity to the River Clyde.
"Approximately 200,000 cubic metres of earth has been excavated to create the underpass . In addition, as the site sits below the level of the river, the creation of 40 pumping wells operating 24/7 was essential to drain groundwater and allow construction to progress."