The challenge of socio-economic data for the western cape travel and land use model

Abstract

Transport and land use models are famously data-intensive, requiring huge amounts of data on demographic and economic conditions at a high level of geographic detail. This information is needed for model development, calibration, and application. The new Western Cape Land Use and Transport Interaction (WCLUTI) model was especially ambitious, as it represents combined and connected models for transport and land use. Transport models require information on the demographics of travellers, since most of their travel choices are influenced by their socioeconomic conditions. Land use models require even greater amounts of information, in order to accurately describe the supply, demand, and pricing of land and the relationships among those elements. Obtaining the necessary data at a high level of geographic detail is always challenging. Problems include public agencies that may be reluctant to share information, inconsistent data collection, and data that exists in different forms and for different years. The Western Cape project addressed these issues by assembling the most accurate possible picture of observed travel and development from many different sources. Both public and private data sources were used. A large effort was spent on reducing inconsistencies between datasets. For example, satellite imagery and GIS tools were used to establish equivalencies between population and employment data at the Small Area Layer and at the Enumeration District layer. The data that was finally used represents an amalgam of different information, representing different geographies and different years. In addition, the data being used for this model is never considered “final”. As new information is made available, earlier data is made more detailed and accurate. This is a continuous activity that will be built into the model development process.