The aim of this study is to develop relationships between the size of the actual road network in a city and the size of the corresponding network model, of the kind required for transport network analysis. Network models of the lowest level of detail possible are considered. These relationships provide the information necessary for an investigation into the effects of variations in the level of spatial detail in transportation planning. In two different city districts complete count of intersections, street sections and regions (building blocks) of the actual road network has been carried out. The same has been done for the corresponding network models in both areas. Relationships are established between a) numbers of nodes (model) and intersections (actual); b) numbers of links and street sections; c) numbers of centroids and regions. Considerable differences exist between the two districts. They can be explained by the network structure expressed in the so called beta-index. On this basis predictive models for total cities have been developed for the numbers of network model elements.
Abstract