Improvement work will start after the August bank holiday at Bences Garage Junction, where the A39 connects with the A368, at Marksbury. The road layout will be changed to include a new lane.
The investment of £890,000 will include £700,000 from the Local Growth Fund administered by the West of England Combined Authority. The project will build on improvements made last year to the Two Headed Man junction on the A39, which was also partially funded through the LGF.