Junction Modelling

Modern roundabouts are widely used in Europe and Australasia and are becoming increasingly common in North America as a viable alternative to traffic signals and priority intersections. Paramics has been used extensively around the world for modelling some of the largest, most complex junctions and roundabouts.

Complex Junctions

Paramics' simple to use link and node network structure makes it quick and easy to construct complex junction layouts. Paramics also features an Intelligent Geometry Engine that will automatically calculate junction priorities, turning speeds, link speeds due to curvature and gradient, multi link zone loading distributions etc. based on the network layout you draw. Of course all values can be further refined by the user to add more detail to the simulation.


In Paramics a roundabout is not simply a series of connected T junctions but a single entity governed by an underlying behaviour model, specifically derived from established roundabout modelling theory deployed worldwide for more than 20 years. Creating a roundabout intersection in Paramics requires a single mouse click followed by optional refinement of behavioural components such as approach visibility, spiral turning lanes and gap acceptance.

A Large Complex Junction showing a projected path highlighted by the Route Viewer tool
A Large Complex Junction
The Hotspot Viewer tool highlighting areas of congestion The HotSpot Viewer

Junction Types

The Paramics software can be used to model all standard junction types such as Priority T, All Way Stop, Ramp Merge, Freeway Off-Ramp, Signalised and Fully Actuated, Diamond Interchange and Grade Separated. In addition many non-standard intersection layouts can be modelled for example Continuous Green T, Diverging Diamond and Continuous Flow Intersections.


Customer Success Stories




  • Single click roundabout creation
  • Up to 16 connected arms to each intersection
  • Signalised or priority
  • Yellow box behaviour
  • Up to 32 signalised phases per intersection
  • Connection to external hardware controllers


  • Priority T and all way stop
  • Ramp merge and diverge
  • Complex weaving areas
  • Fixed time or actuated signals
  • Grade separated intersections
  • Continuous green T
  • Diverging diamond
  • Continuous flow intersections


  • Standard LOS and MOE
  • Stop times and number of vehicle stops
  • Green time utilisation
  • Intersection capacity analysis
  • Queue analysis
  • Turning delay
Comprehensive Feature List
Case Studies
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