A small section of the Copthorne roundabout in Slough will be closed this weekend as part of on-going improvement works.
Part of the roundabout on the A355 Tuns Lane will be blocked off between 7.30am on Saturday and 5.30pm on Sunday.
No entrances or exits to the roundabout will be closed and traffic between the Tuns junction and the M4 will not be affected.
However, motorists will not be able to use the southern circulatory section of the roundabout to access Cippenham Lane. To get to Cippenham Lane motorists will be diverted to the M4 roundabout and back up.
The £5.5m Tuns Lane improvement scheme will turn the Copthorne roundabout - the junction of Tuns Lane with Church Street and Cippenham Lane - into a so-called hamburger roundabout, where the main carriageway goes straight through the middle of the junction.
The roundabout will also get a new 'intelligent' traffic light system which senses traffic jams and adjusts the sequencing of the lights accordingly.
Work is expected to finish in October. Further closures are expected on Saturday, July 30 and Sunday, July 31, and between August 1-6. Slough Borough Council has said further details will be released once confirmed.