TransPosition provided scenario analysis of demand on QML roads using TransPosition’s 4S model of South East Queensland during the bid for Queensland Motorways Ltd. The Queensland Motorways road network comprises the Gateway Motorway, Gateway Bridges, Logan Motorway, CLEM7 and the Go Between Bridge.
In the past few years, the modelling of toll roads in Australia has been relatively poor with reality being far from predictions. The Hastings consortium were intrigued with the 4S model approach for modelling toll roads after reading TransPosition's paper "Modelling toll roads - where have we gone wrong?" which ultimately won TransPosition the job. In the paper above, Peter Davidson describes where we have possibly gone wrong with modelling toll roads and also explains why the 4S model could be an enticing option for the future modelling of toll roads.
Davidson explains that the 4S model (Segmented Stochastic Slice Simulation) has all aspects of choice integrated which allows destination and mode choices to be influenced by value of time and road tolls. Another advantage of the 4S model for the modelling of toll roads is that it deals with time explicitly and allows for time-varying demands. Therefore, tolls that vary throughout the day can also be considered. These aspects of the model only name a few of the many advantages that the 4S model has over traditional models when modelling toll roads and is the main reason that TransPosition was engaged to assist in the QML bid.
See the paper below for further explanation of TransPosition's 4S model.