Fundamental diagrams in traffic flow: the case of heterogeneous kinetic models

TL;DR

This paper introduces a kinetic theory-based traffic model that accounts for vehicle heterogeneity, such as different vehicle types, to better explain the peculiarities observed in fundamental traffic diagrams.

Contribution

It develops a novel heterogeneous kinetic traffic model that incorporates multiple vehicle populations with distinct characteristics, enhancing understanding of congested traffic data.

Findings

The model explains the scattering in congested traffic data.

Heterogeneity influences the shape of fundamental diagrams.

Insights into traffic flow variability in mixed vehicle populations.

Abstract

Experimental studies on vehicular traffic provide data on quantities like density, flux, and mean speed of the vehicles. However, the diagrams relating these variables (the fundamental and speed diagrams) show some peculiarities not yet fully reproduced nor explained by mathematical models. In this paper, resting on the methods of kinetic theory, we introduce a new traffic model which takes into account the heterogeneous nature of the flow of vehicles along a road. In more detail, the model considers traffic as a mixture of two or more populations of vehicles (e.g., cars and trucks) with different microscopic characteristics, in particular different lengths and/or maximum speeds. With this approach we gain some insights into the scattering of the data in the regime of congested traffic clearly shown by actual measurements.