PTV Vissim Drives Success for Innovative Key Junction Upgrade

PTV Vissim software models supported an innovative upgrade of a key junction in England that has led to a significant reduction in congestion since its opening in 2021.

National Highways is the government-owned company that operates and maintains England's motorways and major A roads. As part of its improvement plans, it developed an innovative scheme to upgrade Chowns Mill, a key junction between the A45 and A6 in Northamptonshire, East Midlands.

The upgrade involved replacing the existing priority roundabout with an innovative signalized 'throughabout' junction. A throughabout is a roundabout that has been converted into a signalized junction with traffic lanes running down its center.

PTV Vissim was used during the development of the scheme to demonstrate the operation and capacity of the junction. PTV Vissim also provided parameters for coding the scheme into the strategic evaluation model.

Visualizations of the PTV Vissim model were also used in discussions with stakeholders and members of the public, who were concerned that the layout might not work effectively. The visualizations demonstrated both the level of assessment that had been carried out, and how the intersection signals would be managed to coordinate the complex mix of movements through it.

The roundabout opened in December 2021. The new layout has significantly improved congestion and has received overwhelmingly positive feedback since its completion. 

Learn more about this project in this document.