A week of work is due to start on a scheme to improve traffic flow at Patchway roundabout on the A38.
The road layout will be altered to allow a new bus lane to end some way before the roundabout allowing general traffic to approach using both lanes.
The extra road space should double the number of vehicles able to travel through the junction, and help reduce build up of traffic on Highwood Road.
It should also allow traffic coming from Coniston Road onto the roundabout.
At present, the left hand lane approaching the roundabout from Highwood Road is left turn only which creates delays as the majority of traffic goes straight over the roundabout.
"Many people from throughout the south west enjoy shopping at Cribbs Causeway but, unfortunately this creates traffic congestion in the surrounding area," said Councillor Pat Hockey of South Gloucestershire Council.
"We understand how frustrating this can be so we are introducing this scheme as part of a series of measures to improve traffic flow."
Currently the roundabout suffers from traffic congestion, particularly at peak times and during the busy Christmas period.