Five weeks of maintenance are under way at the A90 Cowie Bridge at Stonehaven.
The work began on Sunday in a £130,000 project involving upgrading the safety barriers and bridge parapets.
It will take place between 7.30pm and 6.30am each night, with no work taking place on Saturday or Sunday nights.
Single lane closures will be in place on each carriageway during the improvements with all traffic management measures removed during the day and at weekends.
Andy Thompson, BEAR Scotland’s North East representative, said: “These essential maintenance works will help ensure Cowie Bridge remains in a safe working condition for years to come.
“We’ve planned these works to minimise disruption as much as possible by scheduling the works to take place overnight and ensuring at least one lane on each side of the carriageway will remain open on the bridge during the project.
“We’re also avoiding working on Saturday on Sunday nights during the project with the exception of the first weekend when our teams will be working overnight to ensure the project can be completed in the shortest available timescale.”
He added: “We thank motorists for their patience in advance while our teams carry out these essential works on Cowie Bridge.
“We encourage road users to plan their journeys in advance by checking the Traffic Scotland website for up to date journey information and leave some extra time for their journey.”
Around 12 weeks of work were carried out on Cowie Bridge last summer involving £1 million of improvements.
It included carriageway resurfacing, concrete repairs and kerb upgrades.