The Braess Paradox in Dynamic Traffic

TL;DR

This paper investigates the Braess Paradox in dynamic traffic networks using microsimulation, demonstrating that adding roads can counter-intuitively increase congestion in real-world-like conditions.

Contribution

It introduces a dynamic traffic network model and empirically validates the Braess Paradox under realistic traffic dynamics using microsimulation.

Findings

Adding a path can increase overall travel time.

Network flow and capacity are affected by added roads.

The Braess Paradox occurs under certain dynamic conditions.

Abstract

The Braess's Paradox (BP) is the observation that adding one or more roads to the existing road network will counter-intuitively increase traffic congestion and slow down the overall traffic flow. Previously, the existence of the BP is modeled using the static traffic assignment model, which solves for the user equilibrium subject to network flow conservation to find the equilibrium state and distributes all vehicles instantaneously. Such approach neglects the dynamic nature of real-world traffic, including vehicle behaviors and the interaction between vehicles and the infrastructure. As such, this article proposes a dynamic traffic network model and empirically validates the existence of the BP under dynamic traffic. In particular, we use microsimulation environment to study the impacts of an added path on a grid network. We explore how the network flow, vehicle travel time, and network capacity respond, as well as when the BP will occur.