Traffic lights at the St Marks retail park and the University of Lincoln car park will be replaced in February, leading to four weeks of additional road works.
Work is set to start on Monday, February 4, 2019.
Although Ropewalk will remain open to traffic throughout the project, temporary lane closures will be in place.
In addition, traffic will be stopped from turning right out of The Sidings (the access road to St Marks retail park) with those wishing to travel towards the High Street being diverted via the nearby roundabout and back on to Ropewalk.
Similarly, vehicles leaving the university car park will be prevented from turning right and will be diverted towards the High Street.
Traffic heading south will be directed to continue along the High Street, whereas those going north will be diverted along the East-West Link Road to Pelham Bridge.
A highways spokesperson at Lincolnshire County Council said: “The lights are reaching the end of their life so we need to replace them.
“The new signals will be easier to maintain and much more energy efficient, saving on annual running costs.
“There will be some disruption while the work is carried out, and we apologise for any inconvenience caused in advance.
“We’d advise motorists to leave additional time for their journeys and use alternative routes where possible.”