The flyover at Chelmsford’s Army and Navy roundabout will close tonight (Friday, 18 March) from 9pm.
The closure is to allow preventative maintenance.
Highways engineers have identified a weakened section supporting the carriageway deck, which requires urgent repair.
Cllr Eddie Johnson, Essex County Council Cabinet Member for Highways and Transport Delivery, said: “We are closing the flyover overnight for essential repair work. It will reopen as soon as possible, most likely during Saturday.
“We apologise for any inconvenience, but hope residents understand that the first concern must always be for the safety of motorists and the general public in Essex. Engineers have acted swiftly following a regular inspection and works will be aimed at causing as little disruption as possible.
“We urge drivers to take extra care when using the Army and Navy roundabout, as we may have to impose temporary lane restrictions while engineers bring in heavy materials and equipment.”