A building society has threatened to pull out of a Kent town, and out of the county completely, unless a decision to demolish a flyover is reversed.
The closure of the flyover led to confusion on two-way switch day
Complaints that Chatham's two-way ring road has affected trade and journey times have mounted since it was changed from a one-way system last September.
Phase two of the changes includes the loss of the Sir John Hawkins flyover.
Mike Lazenby, of the Kent Reliance Building Society, said it was an issue affecting people's livelihoods.
Drop in sales
"Our business has been affected and we've actually had a lot of people come to visit us who've actually been taking the illegal route along Medway Street," the chief executive told BBC Radio Kent.
"We've been in Chatham for 100 years. We had no plans to move up until this point, but if this isn't resolved then we have a very clear idea that we will consider moving outside of Chatham, and possibly outside of Kent."
Labour councillor for the ward, Bill Esterson, said if the building society pulled out it would "start to spell the end for Chatham as a place to shop and work".
David Barrett, secretary of the Chatham Regeneration Action Group, which opposes the changes, said traders had already experienced a 12% drop in sales "up and beyond the recession figures".
"In two of our neighbouring towns - Gravesend and Maidstone - their figures have gone up, benefiting from the traffic in Chatham."
Worried traders, supported by Labour councillors, presented their case at a council meeting on Thursday night.
As a result, the decision to demolish the flyover has been referred back to Medway Council's cabinet for review.
Meanwhile, at a separate meeting on Friday, the council announced that Globe Lane and Medway Street would re-open to passing traffic for a six-month trial period.
"It is a very welcome victory for the vast majority of traders who have campaigned for this change to happen," said Mr Esterson.
"My concern is that once the elections in May are out of the way, and if the Conservatives win, they will just plough on regardless."