Work has got underway on a pavement resurfacing scheme in Dereham which will see a key road in the town shut for about four weeks.
Wellington Road is shut to traffic from July 24 until August 21 between the junctions with Theatre Street and Cowper Road, forcing motorists to take alternative routes.
Signs have been put up at either end of the work saying that businesses are operating as usual but local traders are worried about a serious impact on their livelihoods.
Angela Lane, who runs Through the Looking Glass Interiors in Dereham, says the closure will eliminate passing trade.
Miss Lane, a single mum who opened the store in January, said she expects the impact of the roadworks to be hugely detrimental.
"The closure's going to be a big problem," said Miss Lane, 41. "Every day we get people popping in because they've got a spare five minutes and saw the shop as they drove past.
"I have a good following online, but people in Dereham are still getting to know us so passing trade is what we need. Current customers will always come back - it's the new ones that matter.
"Even if we get five people less every week, that's 25 less over five weeks and that will make a real difference. So many businesses will suffer and I imagine it's going to be a nightmare."
Norfolk County Council say the full closure is "necessary" and "essential to ensure the works are conducted in a safe and efficient manner".
As a result, passengers are being warned that several Konect buses will divert from their usual routes and stop in alternative locations.
"It's all very well putting out signs, but this side of town is going to be gridlocked and people will avoid coming anywhere near," added Miss Lane, who lives in Bradenham. "Limiting traffic to one lane would've been more sensible.
"I expressed my concerns to the council over why it couldn't be done in the winter, but they said it had to be done during the school holidays or it would mess up bus routes.
"I know these things have to happen but people like me plough their lives into their businesses. As a single mum there are people relying on me and we depend on things running smoothly."
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