Highways England is carrying out essential maintenance and strengthening work to the bridge near the junction with the A1058 Coast Road in the Silverlink and Battle Hill areas.
The project had been due to be completed this year but has been extended as a result of additional issues with the structure which has required repairs to the concrete and steel supports.
The latest phase of the project involved moving the scaffolding from the north side of the bridge to the south side. Temporary traffic lights are being used 24 hours a day to allow vehicles to take it in turns to use a single lane on the northbound side of the bridge.
The traffic lights and lane closures will be lifted for 16 days on Friday 18 December to allow traffic to run freely over the Christmas period, before being reinstated on Monday 4 January.
Highways England project manager Michael Hoult said:
We would like to thank drivers and residents for their continued patience while this important work takes place to the A19 bridge over Middle Engine Lane.
This project is necessary to maintain the structural integrity and safe operation of the bridge. If the work is not done now, there could be a need for weight restrictions on the A19 in the future.
We’ll be removing the traffic management restrictions, including the temporary traffic lights, over the festive season before returning to the bridge again in early January.
The project is expected to be completed in spring 2016.
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.