A Simple Representation of a Complex Urban Transport System Based on the Analysis of Transport Demand: The Case of Region Ile-de-France

Abstract

In densely urbanised areas the structure of the transport systems becomes quite complicated. Many types of transportservices are available and many types of modes are being used, thus offering a wide palette of transport options. How do all these transport services and modes relate to each other? In practice it proves to be quite hard to define such a structure. A number of classifications exist, based on transport modes, or on organisational characteristics. However, they often lack a theoretical underpinning, which makes them not always easy to apply in practice. This paper presents a new methodology that focuses on the traveller's perspective: how does the traveller use the many transport services and modes that are available? This method to determines the functional structure of a transport system on the basis of observed trips. This method is illustrated for the case of Region Ile-de-France, the urban area of Paris, using household travel survey data.The methodology consists of three steps. First, transport services and modes are grouped into “service modes”, which are homogenous from the perspective of travellers. Second, the zones served by each service mode are identified. Third, the relationships between the service modes are identified: Spatial complementarity; Hierarchical relationship (combining a fast mode with a scarce network and a slow mode serving a dense network); and Competition. As a result, we obtain a strategic representation of the structure of the urban transport system of Region Ile-de-France.