This paper examines some theoretical aspects of travel time budgets, considers evidence from various sources to judge the validity of this concept, and assesses its use for contemporary transport policy issues. A constant travel time budget could be a very powerful tool, and it could also be very valuable for planning transport for a sustainable future. Various questions about the travel time budget are considered briefly. Some evidence from the National Travel Survey and South Yorkshire household travel panel survey is considered. The evidence suggests that survey methods strongly influence the travel characteristics recorded, and questions the validity of comparing travel characteristics across surveys, except where very similar survey instruments are used. A cross-sectional analysis, using a regression analysis, is made of trip rates, journey time and travel time budgets for different groups of people. The results suggest that, at the individual level, travel time budgets cannot be used to predict how much any one person will travel. However, at the population level, trip time and travel time budgets are more stable than any other easily measurable travel variable. Thus the concept could be used to help forecast future amounts of travel.
Abstract