The route coming on and off Portland onto Weymouth will be partially closed for repairs next month.
Ferry Bridge on the A354 is a vital route for everyone who uses it, including residents, business owners, commuters and visitors.
However, the bridge, which is over 40 years old, has cracks that have formed beneath the surface which need to be repaired to stop further damage.
Now essential repairs to repair that damage will start on 19 January 2026, with traffic signals initially expected to be in place until 1 March 2026.
Cllr Jon Andrews, Cabinet Member for Place, said: “We understand these works will cause inconvenience, and we’re very sorry for that.
“Ferry Bridge is a vital link for Portland and Weymouth, and it’s showing signs of wear. If we don’t act now, the problems could become much worse and lead to longer closures in the future.
“We’re giving everyone this early warning now, so they can plan, talk to families and friends, colleagues and most importantly allow extra time for journeys.
“Doing the work now means the bridge will stay safe and strong for many years to come. We want to thank people for their patience while we make the bridge safe for everyone.”
From 19 January, the road will be reduced to one lane with two-way traffic lights working all day and night. The east footpath will also be closed. Access will be retained for pedestrians and cyclists on the west footpath, although at times there may be slight delays to ensure safe passage.
During the roadworks, abnormally heavy vehicles that exceed normal legal limits, will not be allowed to use the bridge.
This part of the repair programme is expected to be in place until 1 March.
Constructors might need additional, but shorter, periods of traffic signals after 1 March. Advanced warning notice will be provided nearer the time.
During the later stages of the work, two short night-time full road closures of about two to three hours will be required. These are likely to be in April and advance notice of these will be given. Only emergency services will be permitted access during these closures.
Most of the work to repair the bridge will be taking place underneath and will be out of sight.
Regular updates will be provided throughout the works.
