Construction of a dual carriageway in Ashford has been delayed until at least 2022, council bosses have revealed.
Work on the £26 million project, which will widen Chart Road between the tank and Matalan roundabouts, was due to begin in 2018 after scores of trees were felled.
Kent County Council was due to forward fund the scheme, with Hodson Developments - the company behind the first phase of the 5,750-home Chilmington Green scheme - expected to pay back the bill over 10 years.
The agreement between the firm and the authority rested on a security bond from Hodson ahead of awarding a construction contract.
But the security bond - which was requested by KCC in December 2017 - has not been forthcoming, and the work still hasn't begun despite completion being originally scheduled for this autumn.
A planning condition states the developer's money will be released once 400 homes are occupied at Chilmington.
Ashford Borough Council (ABC) cabinet member Cllr Peter Feacey (Con), who lives on Godinton Park close to the road, says it is not clear when the security bond will be paid.
The bond was due to safeguard KCC against any risk of non-repayment and to recover interest charge, but without it bosses say they do not have the financial security to continue with the project.
"It all depends on Hodson - it's 400 homes that need to be bought up," Cllr Feacey said.
"The trouble is we don't really know when that will happen, sales could be slow or very rapid.
"The road's going to be a major part of the town's infrastructure and at the moment it's very difficult to get through in either direction."
When asked if the bond condition could have been set at a lower occupancy, Cllr Feacey said: "I don't know, I wasn't a party in the negotiations with Chilmington.
"400 homes could be an extra 800 cars on the road, but any infrastructure project moving forward is a good thing.
"There's not a lot I can say about it - it is what it is."
In a statement, Thomas Hodson, director of Hodson Developments, confirmed the first residents have now moved into the Chilmington Green scheme.
He said: "In line with the legal agreements attached to the planning permission for the Chilmington Green project, the developers have always only been required to provide finance to Kent County Council to upgrade the A28 upon the 400th house being occupied at Chilmington.
"Chilmington was launched in June 2019 and has proven to be a great success with residents currently living there.
"The 400th occupation is expected to be in 2022.
"Hodson Developments and the developers have met every financial and planning obligation set out in the planning permission agreements.
"This includes a £6m payment plus land to KCC for the construction of Chilmington Green Primary School which is due to open at Chilmington in 2020."
A KCC spokesman confirmed the project - which is due to feature a new bridge over the railway line by the former Chart Leacon works - is currently postponed.
He said: "It is predicted to recommence in 2022 or 2023 when the developer of Chilmington reaches their planning obligation to providing funding to the project, once 400 homes have been occupied."