Highways bosses have been forced to close a section of the A4174 ring road after a manhole collaped.
Emergency repairs are now taking place and one lane has been shut near to oldharbour Lane, in Filton and the junction with the University of the West of England
From 8pm a full closure will be in place until 6am on Wednesday.
A diversion route will be down Coldharbour Lane to the roundabout and back up to the ring road.
A spokesperson for South Gloucestershire Council StreetCare posted on Facebook: These restrictions will cause significant congestion so please plan ahead and avoid the area if possible.
"We apologise for the inconvenience."
