Night-time closures begin on Uckfield by-pass tonight as works progress to a new phase on building a roundabout to serve the Ridgewood Farm development.
This week the by-pass will be closed each night, Monday to Thursday, from 8pm to 5am.
From next week the night-time closures are expected to be in place Monday to Friday until early December.
Traffic will be diverted via Uckfield town centre.
Information on variable message signs in the area will be kept up-to-date to give motorists and residents the latest news.
The new roundabout is being funded by the developer of the housing estate which will eventually accommodate 1,000 homes.
Work began in August accompanied by a 30mph speed limit. The work was expected then to take a total of seven months.