Exploring the potential of aggregated traffic models for estimating network-wide emissions

Abstract

This paper explores the potential of aggregated traffic models based on the Macroscopic Fundamental Diagram for building a network-wide monitoring system of travel emissions. Such a system consists of two layers. In a bottom layer, an aggregated traffic model predicts the network dynamics. In a top layer, an emission model estimates the total exhaust emissions. This paper discusses how to properly calibrate the aggregated traffic models of the bottom layer, to then estimate the total network emissions. We focus on the calibration of travel distances and the network partition definition. We propose a methodology that utilizes the concept of the detour ratio as a proxy to model real travel distances within the aggregated traffic models. This methodology increases the effectiveness of aggregated traffic models for predicting network-wide emissions in realistic scenarios. We also show that the definition of the network partitioning can significantly influence the total network emissions estimation. • We leverage our knowledge of the MFD dynamics for estimating total network emissions. • A microscopic simulation on the city of Innsbruck, Austria, serves as our ground-truth. • We utilize the COPERT IV model to estimate the emissions. • The results show the importance of the calibration of travel distances and network partitioning. • We propose a methodology based on the detour ratio to determine the travel distances.