Year: 2025
Type: article
Abstract: Collective phenomena involving motorcycles in mixed traffic, and more generally bicycles and other new micromobilities in cities, are of great interest, as the behavior of these vulnerable road users raises major safety concerns. This is especially true when the limited urban infrastructure is shared with conventional vehicles, such as cars. However, this topic is severely understudied from a physics point of view and a solid theoretical foundation of multispecies traffic does not exist. By studying the pNEUMA dataset, we first establish a nonlinear relationship between maneuverability and speed, which maps to the nonequilibrium concept of a sample space reducing process (SSR). Coupling SSR with Newell’s nonlinear traffic model, we identify a power-law relationship between the average maneuverability (interpreted as temperature) and the mean speed difference between motorcycle and car populations. Simulation results allow us to recover a nonequilibrium phase transition from an ordered state of lane formation to a disordered state of cluster formation governed by a universal scaling exponent that is robust to traffic conditions and model variants. Our contribution creates a link between microscopic behaviors and the macroscopic theory of percolation. Collective phenomena involving motorcycles, bicycles, and other micromobilities raise significant safety concerns, especially when limited urban infrastructure is shared with conventional vehicles, such as cars. This study proposes a nonequilibrium model for multispecies traffic justified by empirical evidence from the pNEUMA field experiment in Athens, Greece, and unveils a universal scaling law using the concepts of directed percolation.
Source: Communications Physics
Institution: École Polytechnique Fédérale de Lausanne
Language: English
Subfield: Control and Systems Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,990
OpenAlex ID: W4416414247