The new road will run from the roundabout, east through the Orbiston Street industrial area before passing under the West Coast Main Line railway and on to the Ravenscraig site.
Paths for pedestrians and cyclists will be created on both sides of the new road, with crossing points at key locations.
This is the first part of the £127.2m Ravenscraig Access Infrastructure (RAI) project, which is being funded by North Lanarkshire Council and Glasgow City Region City Deal.
The UK Government is investing half a billion pounds in local infrastructure projects through the Glasgow Deal, helping communities "build back better”, whi le the Scottish Government is contributing the same amount over the next 20 years.
In addition to creating new connections to Motherwell, the wider RAI project will improve connections from Ravenscraig north to the M8 and south to the M74 and is part of plans to regenerate the former steelworks site.
Council depute leader Councillor Paul Kelly said. “By improving access to and from the site, we are opening up more opportunities for investment in business, retail, housing and leisure.
"The new road and active travel links will create many construction and associated jobs over the next couple of years but, more importantly, it is the starting point for Ravenscraig to have a new future where people can live, learn, work, invest and visit.”
Nick Davies, director of Ravenscraig Ltd, added: “The approval of these access improvements unlocks another key stage for Ravenscraig’s and Scotland’s economic recovery.
“We have two thirds of Scotland’s population within 90 minutes’ drive of the site, with the forthcoming City Deal project set to reduce journey times further.
"Combined with its excellent public and active travel infrastructure, we are confident Ravenscraig is solidifying its position as the perfect place for people and businesses to locate in North Lanarkshire and the Central Belt.”