Transport Modelling for Project Managers

This review recommends that Austroads undertakes a major revision of report AP-R621-20. It should be of interest to transport and traffic modelling project managers, guide developers and software users.

A traffic and transport model categorisation system is proposed. This uses the geographic extent of the area to be modelled as the basis of Model Types with clear relationships to the Model Level of Detail and Modelling Technique.

Most software packages have capabilities for modelling intersections and networks, use a mixture of analytical and simulation modelling techniques, and involve macroscopic, mesoscopic and microscopic levels of detail.

Estimation and calibration of key capacity parameters saturation flow, follow-up headway and critical gap as a function of road geometry, traffic flows and signal timings should be enforced for microsimulation and mesosimulation models as used in analytical models.

While analytical models are capable of modelling congestion affects with the analysis of a single peak flow period, microsimulation using individual vehicles needs to use multiple flow period modelling.

The modelling of public transport, bicycles and pedestrians is an essential part of analytical intersection and network models.

In using queue length for model validation, different definitions (back of queue, queue at the start of green period, cycle-average queue as well as their average and percentile values) should be clearly understood.