Obscuring digital route choice information prevents delay-induced congestion

TL;DR

This paper models how outdated traffic information influences collective traffic flow, revealing that delays can cause congestion, but strategies like averaging data or reducing adherence can prevent it.

Contribution

It introduces a minimal model showing how information delays induce traffic oscillations and congestion, offering insights into mitigating such effects in real traffic systems.

Findings

Delays beyond a critical point cause self-organized congestion.

Averaging traffic data over time can prevent delay-induced oscillations.

Reducing adherence to route recommendations can mitigate congestion.

Abstract

Although routing applications increasingly affect individual mobility choices, their impact on collective traffic dynamics remains largely unknown. Smart communication technologies provide accurate traffic data for choosing one route over other alternatives, yet inherent delays undermine the potential usefulness of such information. Here we introduce and analyze a simple model of collective traffic dynamics which result from route choice relying on outdated traffic information. We find for sufficiently small information delays that traffic flows are stable against perturbations. However, delays beyond a bifurcation point induce self-organized flow oscillations of increasing amplitude -- congestion arises. Providing delayed information averaged over sufficiently long periods of time or, more intriguingly, reducing the number of vehicles adhering to the route recommendations may prevent such delay-induced congestion. We reveal the fundamental mechanisms underlying these phenomena in a minimal two-road model and demonstrate their generality in microscopic, agent-based simulations of a road network system. Our findings provide a way to conceptually understand system-wide traffic dynamics caused by broadly used non-instantaneous routing information and suggest how resulting unintended collective traffic states could be avoided.