From average travel time budgets to daily travel time distributions: Appraisal of two conjectures by Kölbl and Helbing and some consequences

An analysis of three travel surveys (in Belgium, France, and Great Britain) is used to investigate two conjectures by Kölbl and Helbing. The first one suggests a relation between mode choice and human energy expenditure for travel, which is assumed to be constant in time and space. The second one is the assumption that the distribution form of daily travel time can be derived from an entropy maximization model. The analysis shows the link with energy expenditure to be questionable but also provides alternative views of travel time analysis. In particular, the distribution of daily travel time is shown to be well approximated by three different models. Weekly travel time expenditure is also shown to present different characteristics than the more commonly used daily ones, reinforcing the argument for inclusion of weekly regularities in travel behavior analysis and modeling.