Final Customer

Transport for New South Wales (TfNSW)

Prime Contractor

GTA Consultants


Sydney, NSW, Australia


June 2017 – November 2017

Sydney CBD Light-Rail Transit Study




TfNSW wanted a wide-area multi-level transport model to test the impact of a range of projects, particularly the introduction of light rail through the city center.


The aim of the South East Light Rail (CSELR) project was to reduce bus congestion in the CBD by providing higher-capacity public transport to hotspots currently served only by buses, such as the cricket ground and the University of NSW.

Project Location

Sydney’s Central Business District (CBD) receives a total of 630,000 incoming trips each weekday, a figure expected to grow to around 775,000 trips (23%) by 2031 . 25% of trips are currently made in private cars but the number of private car trips is expected to remain stable, with public transport absorbing most of the incremental journeys.

Aimsun Solution

The pre-existing microsimulation model did not take into account traffic effects outside Sydney CBD. The new multi-level approach to the operational assessment included the development of a large-scale mesoscopic Aimsun Next model that could account for regional route diversion, as well as microsimulation modelling of smaller pockets that require representation of dynamic individual vehicles in the detailed road network. The hybrid platform would also offer efficient data exchange between Aimsun Next and the static Sydney Traffic Forecasting Model and the Public Transport Project Model.


Sydney’s signalized intersections are controlled by the Sydney Coordinated Adaptive Traffic System (SCATS). The SCATSim interface with the Aimsun Next mesoscopic model provided a precise estimate of the magnitude of traffic issues and the development of more appropriate congestion management plans.

Benefit to Customer

The Sydney CBD model enables a multi-layered assessment of the transport operation of the Sydney CBD including in its scope overall regional impacts for both general traffic and public transport.


The light rail operational model successfully assisted in the evaluation of some major road network and bus plan changes in the Sydney CBD. The results showed that the model was able to accurately forecast congestion patterns and impacts on road users and indeed, the light rail project was successfully deployed by December 2019.

Reason for Success

The use of the Aimsun Next modeling platform, in combination with SCATSim, provided Sydney with a cutting-edge tool that was able to successfully support the development of several demand management and operational transport strategies. The model was able to accurately emulate a SCATS traffic control system at 300+ intersections, a feat that was previously only possible in small-area microscopic level models. It is the attainment of such breadth of scope combined with such depth of detail that makes the Sydney CBD model so innovative.

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