The traffic lights have failed at a major junction in Pilning.
The lights on the A403 Severn Road junction with Redwick Road are currently not working.
There is a fault with the signal controller and which South Gloucestershire Council hope will be fixed by Thursday.
Temporary lights will be in place ahead of this evening's rush hour.
A statement from South Gloucestershire Council's StreetCare team said: "As temporary signals are less intuitive than permanent lights, we need to put some restrictions in place to manage traffic.
"This means all approaches to the junction will be reduced to a single lane.
"Delays are expected and we apologise for this. Thank you for your patience."
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