Modal Split – Different Approaches to a Common Term

Abstract

Abstract The modal split, also known as modal share or mode choice, is a common and widespread indicator in transportation engineering to evaluate transportation behaviour. In brief, the modal split shows the percentage of travellers using a particular mode of transport compared to the ratio of all trips made. For example a higher modal split number of bicycle users indicates a more sustainable city. But when going deeper into the analysis, it turns out that surprising variations in the definition emerge, each with a more or less different meaning. But even if definitions would be crystal clear, the measuring practice makes it almost impossible to regard certain mathematical numbers as the one and only result. However, scientific research still uses it as an indicator. Crucial exact conclusions and result may be drawn from modal split numbers. As the origins date back to the 1960’s, how can this indicator still work? How can it still be the best method to calculate trends in transportation? Isn’t there nowadays a better indicator nowadays? It turns out there is not. Modal split is still the best evaluation method in measuring quality of some regions transportation system. In this article I try a theoretical approach to this term, and also point out practical issues. I give a short overview of the history of modal split, and finally focus on examples based on real cases to explain where problematic approaches can occur.