If a government, a private company or the community wants to build more transport infrastructure or change a policy, or an operating system, how can we evaluate the real consequences, the true worth of going ahead.

We have been computer modeling the transport network for a long time now.

No model is perfect. Are well getting better in this changing world.

And getting better is not just trying to perfect the way we have always done it.

In order to have a manageable model we have often zeroed in on specific tasks such as the journey to work, in the morning peak. We have also assumed that people make logical choices based on just time, cost and distance and we have measured the impact by how well we get vehicles to flow on a road or public transport to run.

Our models are also contained, in that they usually don’t allow for people to move out of the peak periods we are analysing. And while we may change the land-use, the activities that generate trips, according to our designed plan, we don’t often consider how the transport system may impact where jobs, schools, shops and other activities will spring up. The modeling usually takes a long time

The Institute of Transport and Logistics Studies at Sydney University has developed and run their own model with a different approach.

This broadcast is not a workshop on the intricacies of using the model but rather why did it come about, what it is broadly trying to do and what is it leading to in the future.

Prof David Hensher is the founder and director of the Institute and has had a very hands-on role in this project.