The work, which will involve taking down the old central reserve barrier, and installing a new one, will take place between the A11/A14 junction and the Cambridgeshire/Suffolk border, near Red Lodge, from Monday 2 November to Friday 18 December.
During the work, lane 2 of the A11 will be closed in both directions weeknights only between 8pm and 6am.
Highways England project manager Andrew Dyer, said:
This work is necessary to ensure the continued safety of road users on this stretch of the A11.
We have timed the work to be carried out when traffic levels are at their lowest and overnight but we are advising people to allow extra time for their journeys when the closures are in place.
Members of the public should contact the Highways England customer contact centre on 0300 123 5000.
Journalists should contact the Highways England press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.