How Many Cars in the City Are Too Many? Towards Finding the Optimal Modal Split for a Multi-Modal Urban Road Network

Interactions among different modes or vehicle classes in urban road networks affect the network performance and complex ways. Thus, an answer to question of “how many cars are too for a city?” is not trivial. However, multi-modal macroscopic fundamental diagrams (MFD) offer novel opportunity this question. So far, no methodology exists estimate MFDs resulting from arbitrary interactions. In paper, we propose capture additional delays shape MFD derive approach estimating thereof. The influence on established using two-fluid theory traffic by defining pairwise copula functions between travel times each mode. contrast existing approaches, presented retains individual mode's speed information. We show applicability with tri-modal case bicycles, buses, empirical data Amsterdam (The Netherlands) London (United Kingdom). Although limited specific case, use example discuss initial policy deriving optimal modal splits given accumulation travelers. Last, compare new estimation methods bi-modal describing car bus traffic.