Monday morning will be more challenging than usual for commuters going through the Elephant as traffic will start going both ways round the junction.
The notorious roundabout, which has seen more than 80 collisions since 2012, will be replaced by a two-way system on Sunday for the first time in 50 years.
The new set up will mean some routes will no longer be allowed so Transport for London is advising commuters approach the junction with caution.
As part of a £25million redevelopment of the Elephant, the seven subways are also being replaced by above-ground pedestrian crossings and there will also be new dedicated cycle lanes.
The borough-wide 20mph speed limit will be introduced at the junction in the spring.