In transportation planning, traffic on the road is commonly divided into:

1. Urban (internal-internal)
2. Regional (internal-external, external-internal)
3. Through (external-external)

Note that here ‘internal’ refers to zones inside the study area, whereas external refers to zones outside the study area.

These three types of traffic can be easily calculated and visualized in Aimsun using the Select Link Analysis Tool and View Modes.

First you have to define the internal and external areas.

Generate a new grouping category by right clicking group categories and choosing “List of objects of type:” and select “Centroid”. Change the name and check “Exclusive Objects” so zones are exclusively for one group.

Click to enlarge: Defining the internal and external areas

Now draw a polygon around the area that you consider the external area (green) and the study area (red). Create two groupings by right-clicking on the Grouping Category that you have created in the previous step and name them “External Area” and “Internal Area”. Add the zones to each grouping by selecting the objects inside the polygon and adding them to the appropriate grouping.

You can now analyse the traffic with the Select Link Analysis Tool, located in the “Path Assignment” tab of any retrieved Path Assignment object.

Click to enlarge: Analyse the traffic with the Select Link Analysis Tool

Click to enlarge: Creating a view mode that divides the External-External traffic by the total traffic

This figure shows that in some parts of the study area 30-40% of the traffic consists of through traffic. The same can be done for external-interval and internal-internal traffic. You can show the traffic proportions in a pie-chart for each section.

Click to enlarge: This figure shows that in some parts of the study area 30-40% of the traffic consists of through traffic