The York Street, A5 and A6 road projects must be a priority for the Executive to quickly help the Northern Ireland economy, it has been warned.
The call came after Belfast was listed among the most congested cities in Europe, with projections that £800 million could be lost to the economy in traffic jams by 2025.
Traffic analysis company Inrix surveyed roads use in 123 cities across Europe over the past year using data from satellite navigations systems, mobile phones and road sensors.
It then ranked the cities in terms of 'traffic hotspots' - when congestion forces the driver to cut their speed by 65% for at least two minutes.
The UK was found to be the worst in Europe with 20,000-plus hotspots in cities with a population of 250,000 or more.
And Belfast was the 10th worst in the UK.
Report authors found there were 446 traffic hotspots in the city, with the worst being the junction of the Westlink and York Street.
The busy Belfast intersection carries 100,000 vehicles each day and the Department for Infrastructure is in the process of progressing with the long-awaited York Street Interchange project, that will in effect do away with junctions which snarl up traffic at the point the A12, M2 and M3 converge.
A formal public notice of the department's intention to proceed with the project was made yesterday. However, doubt remains over funding.
Infrasturcture Minister Chris Hazzard has described the project as an "important step" in addressing continuing delays and congestion.
And while it is a priority for the Sinn Fein minister, a £130m shortfall in funding remains a "major challenge" given the competing projects in his department.
The Inrix report also found that congestion in Belfast was estimated to cost the Northern Ireland economy £800m by 2025.
Graham Cookson, chief economist at Inrix, said: "Only by identifying traffic hotspots and analysing their root causes can we effectively combat congestion.
"Some of the most effective traffic improvement measures have benefited from this approach."
Chancellor Philip Hammond recently made more than £250m available to the Executive for infrastructure projects.
Ulster Unionist MLA Steve Aiken said given that injection of cash, it was imperative work on the York Street Interchange project was started "and completed quickly".
He said: "This is an opportunity to prioritise the work, to get it built, and in parallel with the A5 and A6 work.
"It is not an issue about improving Belfast, it is about improving transport links for Northern Ireland and for the north of Ireland and beyond.
"One of the key economic indicators for growth is good transport links.
"That means having the logistics in place to transport goods around the place and not having workers snarled up in traffic jams.
"Low productivity rates are one of the weaknesses of our economy and we need to raise them, and these road projects are a way to do that and quickly.
"And if we can do that it will be a 'win, win' for all people of Northern Ireland and the economy."