1 Setting up a Continuous Panel for Collecting Travelling Information: Discussion on Methodological Issues Elke Moons, Geert Wets

Modelling travel behaviour has always been a major area of concern in transportation research. Since 1950, due to the rapid increase in car ownership and car use in Western Europe and in the US; several models of transport mode, route choice and destination have been used by transportation planners. The most recent models clearly indicate that the use of household travel data is a critical component of the travel-demand forecasting process. The data are typically generated through a household-based survey in which a sample of the population records their travel patterns over a given time period. This information is combined with socio-demographic information about the sample to develop relationships between individual/household characteristics and their observed travel patterns. Traditionally, travel data on households and individuals is collected cross-sectionally every five years in Flanders on two thousand five hundred households that have to report their travel behaviour for two consecutive days. This means that if we want to investigate the changes from one wave to another, we can only speak in terms of moving averages over five years. It has been established that calendar events (holidays, long weekends, etc.) have a serious impact on travel demand. However, the effect of these regular events has never been combined with differen