Nottinghamshire County Council is urging local businesses to back its bid to bring forward the widening of the A453.
The county council has already written to transport secretary Philip Hammond pledging £20M towards the cost of widening the route.
Now county council leader Kay Cutts has written to major businesses in the region, urging them to support the bid.
“The importance of improving the A453 to Nottinghamshire and the regional economy cannot be underestimated,” said Cutts in the letter.
“That is why Nottinghamshire County Council has offered £20M towards the cost of widening this vital route in the hope that the government will bring forward its approval.
“But in order to maximise our chance of success we need to gather pledges of support from as many local businesses as possible.”
The A453 is one of the most congested roads in the country and costs larger businesses as much as £100,000 a year because of increased fuel usage, lack of access to customers, abandoned journeys and accident costs.
To the region as a whole, it has been estimated that an improved A453 would bring a boost to the economy of £540M.
The widening of the A453 is believed to be one of just a few reserve schemes on a government shortlist to be brought forward for construction to begin before 2015. Latest cost estimates for the scheme are just over £160M.