Roads and Maritime Services maintains a strategic traffic forecasting model using software known as EMME (Equilibrium Model/Multimodal Equilibrium). EMME is a travel demand modelling system used for urban, regional and national transportation forecasting.
Roads and Maritime uses transport forecasting software (EMME), to undertake traffic modelling and forecasting of road schemes with wide-reaching network impacts, and to examine the effects of significant new residential or employment land releases, major incidents, tolling or other strategies.
In basic terms the model comprises a base road network and a number of zones, similar to suburbs or parts of suburbs. For each of these zones, Roads and Maritime receives information of population and employment forecasts from the NSW Bureau of Transport Statistics. This information also includes information about trips between zones. In modelling terms this is known as origin and destination information. The model generates trips between zones based on the land use information and trip patterns. The trips are assigned dynamically within the EMME model to the route or combination of connecting roads, that provides the overall shortest travel time between the starting zone, the origin, and the ending zone, the destination.
Further information can be found on the Bureau of Transport Statistics webpage, in particular, the following documents:
- Strategic Travel Model (STM) Assumptions - BTS InfoSheet February 2012; and
- Sydney Strategic Travel Model (STM) February 2011 – Modelling future travel patterns.
The models are calibrated for the 7am to 9am and 4pm to 6pm peak hours based on actual survey traffic data for the principal routes within the model to ensure they are providing an accurate representation of real world travel patterns.
Once the base year has been established and successfully calibrated, travel patterns can be forecast for future years. The future year forecasts rely on the population and employment forecasts and assumptions about the state of the future road network. For example, modelling of the South West region of Sydney for 2011 would include a two lane undivided Camden Valley Way. Modelling for 2016 would include a four lane divided Camden Valley Way.
Details of existing and predicted population growth forecasts, employment growth forecast, modes of traffic and Annualised Average Daily Traffic counts and forecasts are also provided in Appendix B of the REF. RMS has undertaken 'sensitivity analysis' in anticipation of potential traffic forecast variation.