The 4S Model
The TransPosition 4S model has been developed over the last 7 years and has contributed to the planning of over $9 billion worth of transport infrastructure.
The 4S model has been developed with the philosophy of having a realistic and powerful foundation, with system-wide parameters and minimal localised overrides. This approach was partly developed out of frustration with the lack of soundness and flexibility to the older models.
TransPosition’s new modelling approach overcomes many of the deficiencies of the traditional four step transport model, particularly with respect to modelling non-car modes and behaviour change—the Segmented Stochastic Slice Simulation Model (4S Model). Click here for published documents on the 4S Model.
The following sections step through the description of the 4S Model; the network, behavioural and land use assumptions used in the model; and also how we combine large amounts of data from different sources.