Motorists in Abingdon still coming to terms with the new Stratton Way layout face more problems during the next 18 months.

The town's two main roads, Stert Street and High Street, could face closure when work starts next year on the final phase of the revamped road network. Traders and drivers can expect further delays next year and in 2008.

It is not certain yet which of the two streets will be chosen first for conversion into a single lane with wider pavements.

Closures would be the last resort, said the county council's senior project engineer Andy Warren.

He said: "The big problem would involve traffic coming from north Abingdon wanting to go down Stert Street and over the bridge. It would have to go via Stratton Way, Drayton Road and Sutton Courtenay, or we might have to look at a temporary two-way High Street.

"We would have to make allowances for buses and lorries and there would have to be clear areas for safe working."

Abingdon also faces other upheavals. The Market Place will be closed for two months from the middle of January and later in the year when work is expected to start on improvements to the Bury Street shopping precinct.

The Monday market will be transferred to the car park in Abbey Close.

Jennifer Corrigan, who runs the Jennifer Gerard art gallery in Stert Street, said: "Abingdon has suffered a lot of disruption and now we face more upheaval.

"It is putting a lot of pressure on businesses at a time when we need all the help we can get. Street closures in Stert Street and High Street are the last thing we want."

Chamber of commerce president Jill Carver said: "I hope closures can be avoided and maybe they will only be short term. There will be some disruption but we are in this for the long term, and I am confident that the changes will lead to a much better future for Abingdon."

Work on phase two will begin in the summer. It includes improving access for cyclists and pedestrians. In addition, a 20mph zone will be introduced.