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
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
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.
Papers presented virtually at the 39th International Southern African Transport Conference on 05 -07 July 2021