A leading traffic expert at the University of Sydney Business School says New South Wales' model for forecasting traffic flows is six decades out of date.

Dr. Michiel Bliemer is the Chair in Transport Network Modelling in the Business School's Institute of Transport and Logistic Studies (ITLS).  The professor says the NSW government knows that its modelling is based in "unrealistic assumptions of traffic flows".

"The models that are being used today are based on the same assumptions that we made in the 1950s when there was virtually no congestion," said Dr. Bliemer, as quoted by Logistics and Materials Handling Magazine.  "These models still assume that congestion is very light and that queues are unlikely to form anywhere in the network."

He adds, "It's a bit like going to the supermarket.  The 1950s model assumes that there are always enough checkouts and that queues will never form.  When it comes to our roads, that kind of assumption is no longer valid, especially in Sydney where we have a lot of congestion that impacts on traveling times and that cannot be predicted by the old model."

Bliemer says the Sydney region's needs have changed as road networks became more complex.

"We have to be able to model the movements of 4 million people all at onc" he said.  "We need to know how many are moving from home to work or going shopping every single day.  The model needs to predict how many people are using a single road and the travel times they face."