After National Highways announced it was pausing the project, business leaders worry that plans to improve a busy road will be "buried in the long grass.".
The A303 in Somerset was scheduled to get dual carriageway upgrades.
80.5 miles of the A358 at Southfields that connect to Taunton's Junction 25 of the M5 were also scheduled for expansion.
However, National Highways stated that it was considering proposals to lessen the environmental impact before Christmas.
The statement read: "With the backing of the government, National Highways has chosen to pause the development consent order application while we support a review into the environmental mitigation proposed for the project, delaying the submission date into 2023. ".
South West Business Council Chairman Tim Jones told the BBC: "I strongly suspect that this scheme is going to get lost in the weeds given what we are hearing from Whitehall right now about reduced budgets and restricted expenditure. ".
The A303 required investment, according to Loungers founder and chairman Alex Reilley, whose restaurant and bar chain has locations in Wales and the southwest.
According to him, "The A303 needs investment because it is obviously a very important road that people will use if they are not traveling along the M4/M5 route.".
When BBC West contacted National Highways, they declined to comment further.