Macroscopic fundamental diagram with volume-delay relationship: model derivation, empirical validation and invariance property

Fuente: arXiv
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Main Authors: Han, Ke, Huang, Tao, Fan, Wenbo, Ge, Qian, Dong, Shihui, Wang, Xuting
Format: Preprint
Published: 2023
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author Han, Ke
Huang, Tao
Fan, Wenbo
Ge, Qian
Dong, Shihui
Wang, Xuting
author_facet Han, Ke
Huang, Tao
Fan, Wenbo
Ge, Qian
Dong, Shihui
Wang, Xuting
contents This paper presents a macroscopic fundamental diagram model with volume-delay relationship (MFD-VD) for road traffic networks, by exploring two new data sources: license plate cameras (LPCs) and road congestion indices (RCIs). We derive a first-order, nonlinear and implicit ordinary differential equation involving the network accumulation (the {\it volume}) and average congestion index (the {\it delay}), and use empirical data from a 266 km$^2$ urban network to fit an accumulation-based MFD with $R^2>0.9$. The issue of incomplete traffic volume observed by the LPCs is addressed with a theoretical derivation of the observability-invariant property: The ratio of traffic volume to the critical value (corresponding to the peak of the MFD) is independent of the (unknown) proportion of those detected vehicles. Conditions for such a property to hold are discussed in theory and verified empirically. This offers a practical way to estimate the ratio-to-critical-value, which is an important indicator of network saturation and efficiency, by simply working with a finite set of LPCs. The significance of our work is the introduction of two new data sources widely available to study empirical MFDs, as well as the removal of the assumptions of full observability, known detection rates, and spatially uniform sensors, which are typically required in conventional approaches based on loop detector and floating car data.
format Preprint
id arxiv_https___arxiv_org_abs_2309_07811
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Macroscopic fundamental diagram with volume-delay relationship: model derivation, empirical validation and invariance property
Han, Ke
Huang, Tao
Fan, Wenbo
Ge, Qian
Dong, Shihui
Wang, Xuting
Physics and Society
This paper presents a macroscopic fundamental diagram model with volume-delay relationship (MFD-VD) for road traffic networks, by exploring two new data sources: license plate cameras (LPCs) and road congestion indices (RCIs). We derive a first-order, nonlinear and implicit ordinary differential equation involving the network accumulation (the {\it volume}) and average congestion index (the {\it delay}), and use empirical data from a 266 km$^2$ urban network to fit an accumulation-based MFD with $R^2>0.9$. The issue of incomplete traffic volume observed by the LPCs is addressed with a theoretical derivation of the observability-invariant property: The ratio of traffic volume to the critical value (corresponding to the peak of the MFD) is independent of the (unknown) proportion of those detected vehicles. Conditions for such a property to hold are discussed in theory and verified empirically. This offers a practical way to estimate the ratio-to-critical-value, which is an important indicator of network saturation and efficiency, by simply working with a finite set of LPCs. The significance of our work is the introduction of two new data sources widely available to study empirical MFDs, as well as the removal of the assumptions of full observability, known detection rates, and spatially uniform sensors, which are typically required in conventional approaches based on loop detector and floating car data.
title Macroscopic fundamental diagram with volume-delay relationship: model derivation, empirical validation and invariance property
topic Physics and Society
url https://arxiv.org/abs/2309.07811