Almost 600 homeowners are claiming compensation, saying the Norwich Northern Distributor Road slashed the value of their houses.
And, some three years after the controversial road fully re-opened, a further 54 land owners are still waiting to get compensation for land taken by the council.
Liberal Democrat county councillor Dan Roper raised questions about the process at a recent meeting of the council's Conservative-controlled cabinet.
Martin Wilby, the council's cabinet member for highways and infrastructure, said more than a hundred landowners had been directly affected - and more than half the claims had been settled.
That means the council has paid just over £2.6m to 50 cases out of 104, not including four sections of land acquired before construction started, which pushes the figure to £3.5m.
Mr Wilby said: "Of the outstanding cases, for over half of them the final figure has been agreed but the formal legal transfer has yet to be completed.
"Of the remaining 25pc of cases, negotiations are continuing with landowners and their representatives/agents but in some instances a compensation claim, or indeed contact from the landowner is still awaited, despite chasing them."
Some £12.7m of advance compensation payments have been made in the majority of the outstanding cases, the council said.
The council said it could not put a figure on what the final cost would be, but said it would be within the £205m bill for the road.
Among those awaiting payment is Hevingham farmer Richard Pointer, who parted with 21 acres of agricultural land at St Faith's to make way for the road.
He said: "We've agreed a price, but it is frustrating because it has been going on for years now."
But it is not just landowners making claims. The council has had 599 claims from householders who argue the road has decreased the value of their homes - and such claims are still coming in.
The council says it is 'resisting' 312 of them, has provisionally agreed 135, while the others are either new or in negotiation.
Mr Wilby said where payments had been found to be valid, he was "optimistic" they would be made in the next two months.
But he said compensation from major infrastructure projects was often a long and complicated process, which had not been helped by the coronavirus pandemic.
Following the meeting, Mr Roper said: "The majority of people contacting me about this are not major landowners, they are residents with straightforward claims about how the road impacts on their home or garden.
"These residents have had to wait for too long to get their claims settled."
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