WORK has begun on alterations to the Harnham Gyratory to try to improve the traffic flow.
Some delays and disruption are expected, but Wiltshire Council says it is confident that rush-hour hold-ups will be reduced once the improvements are |completed.
It has apologised for any inconvenience in the meantime.
The work will take place at night and is due to be finished by the end of the week.
The line of the kerb on the corner of New Bridge Road will be altered to make it easier for buses and lorries to get round.
This will involve the temporary closure of New Bridge Road between the gyratory and Britford Lane West.
A tree and some shrubs at Woodrows Corner will be taken.
However, replacements will be planted.
Diversions will be signposted when the road is closed to northbound |traffic going towards the Exeter Street roundabout.
The closures will take place between 8pm and 7am.
John Thomson, the council’s cabinet member responsible for highways, said: “Carrying out this vital work during the day would have led to severe congestion and lengthy delays.
"I would like to apologise to the people living nearby and the council's contractors will seek to minimise any disruption.”