Four lanes of traffic will be reduced to two while repairs to the Bromley Heath Viaduct on the Avon Ring Road take place, starting in the summer.
A South Gloucestershire Council report projects queues back to the Dramway roundabout beyond Emersons Green, almost three miles (4.8 km) away.
Traffic is also predicted to queue back to the M32 and possibly the M4.
The council said essential repairs, including pier strengthening, parapet replacement and concrete repairs, are needed on the westbound viaduct over the River Frome, which was built in 1968.
A council spokesperson said it was a "major scheme which would involve bridge strengthening and road resurfacing, as well as improved provision for cyclists and pedestrians".
They added that councillors would consider a range of options, including phasing the work over a number of years or doing the work in one go starting this summer.
The issues are due to be heard by the council's Environment and Community Services committee later.
Roadworks on a ring road around Bristol are predicted to cause tailbacks of up to three miles for up to a year.