Abstract:
In 2018, the Western Cape Department of Transport and Public Works retained Bentley
Systems (formerly Citilabs) and Esri SA to develop the Western Cape Land
Use/Transportation Interaction model. This model provides the ability to test a wide variety
of demographic and multimodal transport system changes in support of a new
performance-based planning process. This model is innovative and unique in several
respects:
1) It is an integrated person travel/goods movement/land use forecasting process, in
which the transport system influences growth, which in turn influences the system.
2) The person travel model uses the new type of tour-based structure. Instead of zonal
averages, choice probabilities are used to simulate the decisions of individual
travellers.
3) Land use is modelled applying bid-rent mechanics to achieve an equilibrium between
real estate supply and demand and accounts for informal development.
4) The goods movement component uses a commodity flow model, translating
macroeconomic and demographic data into the flow of material by mode and
estimating truck travel on roads.
Developing a new travel model usually requires significant data on demographics and
existing travel patterns, which is largely unavailable in South Africa. Thus, the models are
crafted from a combination of local information and behaviour transferred from other areas.
The household synthesis component was calibrated from Stats SA data. Demand is
estimated using several components: tour frequency, destination choice, mode choice,
intermediate stops, time of day, and trip assignment. The model is developed using Cube
software. As of mid-2020, the model system was calibrated, tested, and documented. The
project’s final year will see some enhancements, more testing, and additional staff training.
