The Four-step Model experiment in Aimsun allows the user to organize all of the processes in a chain. The advantages are twofold: this allows the execution of the whole experiment in one run with no need for scripting, and the experiment will help to keep track of the steps executed and relate inputs and outputs.

A four-step model experiment

Four-step model experiment

Each box corresponds to an input (vectors, matrices) or experiment to be executed (Generation/Attraction experiment, Distribution+Modal Split experiment, Assignment experiment). Each box also corresponds to an Aimsun object; the values and parameters must be set in the object itself (matrix, vector or experiment) and not in the Four-step Model experiment. If you want, you can change the name of the box to make the diagram more descriptive.

Each box corresponds to an input and an object

Lines connecting the boxes also contain information; you can select which information in the preceding box is relevant and should be used by the next box. Click on any connecting line to show and select the corresponding data:

Lines connecting the boxes also contain information