How many cars in the city are too many?

Towards finding the optimal modal split for a multi-modal urban road network


Date

2021-05

Publication Type

Journal Article

ETH Bibliography

yes

Citations

Altmetric

Data

Abstract

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

Publication status

published

Editor

Book title

Volume

2

Pages / Article No.

665006

Publisher

Frontiers Media

Event

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Macroscopic Fundamental Diagram (MFD); Two-fluid theory; Multi-modal; Bicycle; Bus

Organisational unit

03521 - Axhausen, Kay W. (emeritus) / Axhausen, Kay W. (emeritus) check_circle
02655 - Netzwerk Stadt u. Landschaft ARCH u BAUG / Network City and Landscape ARCH and BAUG

Notes

Funding

ETH-04 15-1 - "How many are too many?" (ETHZ)

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