13.4.2 Introduction

The steps in base model development are generally as follows:
  1. General preparation
    • Switch units from metric to US Standard
    • Switch from European fleet to American fleet
    • Add an ortho rectified aerial background photo
  2. Code basic geometry
    • Roadway links, traffic control, turning movement speeds, link level speeds, etc.
  3. Network loading
    • Network loading in Vissim entails adding different vehicle composition/mixes from counts to the network, adding in the different types of vehicles and classes, and adding vehicle inputs. More detail is provided for network loading later in this section.
  4. Set up simulation and run the model
  5. Debug
When starting a new model, take note of the current Vissim software version. Once a file is saved to a new version, it cannot be converted back to the old version. It is best practice to keep the Vissim software version consistent between different models used in the same analysis. There is a potential for considerable differences between Vissim build versions based on the car following algorithm and other underlying principles. Vissim build version is recommended to be kept consistent throughout the course of the project to avoid affecting calibration and overall results. Additional information on Vissim can be found in the Planung Transport Verkehr (PTV) Vissim Help Manual. A link to the PTV Vissim Help Manual is provided in
Appendix N, Section 4 – External References (Reference 1)
.