Fears have been raised about traffic congestion as a busy road in Bury St Edmunds faces being reduced to one lane for at least 18 months.

The Westley railway bridge, near the A14 roundabout in Newmarket Road, is one of the main routes into town for vehicles from the west.

Traffic lights and safety barriers have been installed on the bridge after a series of structural problems were identified in assessments, with repairs expected to last at least 18 months.

County councillor for the town, Mark Ereira-Guyer, said: “We’ve got to act for safety reasons and that’s absolutely appropriate, but the people I represent in Newmarket Road are going to be inconvenienced for a long period of time.”

Mr Ereira-Guyer added the council was pushing for a fixed deadline by which the work will be completed.

A weight limit was introduced on the eastbound lane following an initial assessment by the county council in May, while further assessments have identified more “structural deficiencies”. Traffic lights went live on Thursday, although the 7.5-tonne weight limit has been lifted as traffic over the bridge has gone down to single file.

A Suffolk County Council spokesman said: “We are in discussions with National Rail and our contractors to identify the exact extent of works and the necessary lead-in time needed, therefore the timescale is only an approximate at this stage.

“In carrying out these works we’re able to lift the 7.5-tonne weight restriction on the bridge, allowing heavier goods vehicles to travel over it. We will put in measures to help minimise any disruption caused during this period of works.”

Although traffic yesterday was backed up to the A14 slip road, commuters and local residents all said the rush-hour queues were no worse, and possibly even better, than usual. Commuter Colin Houghton, who travels over the bridge to get to nearby Glasswells, said yesterday: “I didn’t find it too busy, and actually when you got to the other side things were a little bit clearer and less hectic.

“It’s early days, though. You’ve got to wait until the heavy lorries realise they can start going back over there.”

The issue is due to be brought up by councillor Graham Newman, the county council’s head of highways, at the cabinet meeting on Thursday.