Microsimulation modelling of traffic flow on two-way two-lane rural roads: past, present and future

This paper describes how two-way, two-lane roads provide the backbone of the nation's road system in regional Australia and the will continue do so for the foreseeable future. Whilst some aspects of the traffic operations of two-way, two-lane roads are reasonably well understood, there are new factors that have not been subject to intensive study. These include the growing use in volume and spatial coverage of large combination vehicles such as b-doubles. This paper describes research at the Transport Systems Centre in collaboration with Quadstone, the developers of Paramics, to devise a rural two-way, two-lane road simulation module and incorporate it in Paramics. This module allows for high-speed traffic operation with limited overtaking in the face of restricted sight distance or oncoming traffic. It also considers vehicle performance on gradients, including a range of different vehicle types. This research uses the outcomes of previous studies as the basis of the new model, along with collection of new data from rural roads in South Australia. The paper describes applications of the new model to freight vehicle performance on rural roads and of the effects of large vehicle (b-doubles) in rural traffic streams and their interactions with other vehicles. Further developments of the overall model to consider multi-modal transport systems, e.g. the balance between road and rail-based freight transport are outlined.J.C. Fry, M.A.P. Taylor and J.E. Woolle