To Stay or to Bypass: Unraveling Mainline Vehicles' Aggregate Strategic Decision-Making at Highway Weaving Ramps

TL;DR

This work addresses the problem of predicting aggregate lane-choice behavior of mainline through vehicles near highway weaving ramps. It introduces a macroscopic Wardrop-like game-theoretic model that predicts the equilibrium split between steadfast and bypassing through-vehicles, expressed as $\mathbf{x}=(x_1^{s},x_1^{b})$, given a flow configuration $\mathbf{n}$ and affine costs $J_1^{s}$ and $J_1^{b}$ parameterized by $\mathbf{C}$ and $\boldsymbol{\theta}=(\alpha,\beta,\omega,\gamma,\rho,\delta)$. The model is calibrated and validated using SUMO simulations, achieving high predictive accuracy and demonstrating robustness across diverse weaving ramp scenarios; a univariate sensitivity analysis confirms limited data requirements and stable parameter behavior. The approach offers a practical, computationally light framework for analyzing weaving bottlenecks and informing traffic-management strategies with minimal data needs.

Abstract

The weaving ramp scenario is a critical bottleneck in highway networks due to conflicting flows and complex interactions among merging, exiting, and through vehicles. In this work, we propose a game-theoretic model to capture and predict the aggregate lane choice behavior of mainline through vehicles as they approach the weaving zone. Faced with potential conflicts from merging and exiting vehicles, mainline vehicles can either bypass the conflict zone by changing to an adjacent lane or stay steadfast in their current lane. Our model effectively captures these strategic choices using a small set of parameters, requiring only limited traffic measurements for calibration. The model's validity is demonstrated through SUMO simulations, achieving high predictive accuracy. The simplicity and flexibility of the proposed framework make it a practical tool for analyzing bottleneck weaving scenarios and informing traffic management strategies.

Figures (2)

• Figure 1: In the vicinity of a highway weaving ramp, mainline through vehicles (indicated by green vehicles) must decide between two strategies: remaining in their current lane (steadfast behavior, indicated by yellow traces) or shifting to an adjacent lane to bypass the potential conflicts (bypassing behavior, indicated by red traces). The weaving zone involves vehicles merging onto the mainline from the on-ramp and vehicles diverging to leave the highway, creating potential conflicts that influence lane choice decisions. Our model captures the strategic behavior of mainline through vehicles by accurately predicting the proportion of steadfast and bypassing vehicles while maintaining reasonable computational complexity and minimal calibration requirements.
• Figure 2: Validation results demonstrating the strong agreement between our lane choice model and observed simulation outcomes. Despite the cost model's linear structure, the lane choice model successfully captures nonlinear behavior patterns due to the inherent nonlinearity of the equilibrium conditions. Specifically, subfigures (a) and (c) show that an increase in the proportion of exiting vehicles, with a constant flow of entering vehicles, leads to more frequent bypassing behavior by through vehicles on Lane 1, as they shift to Lane 2 to avoid potential congestion. Similarly, a higher proportion of entering vehicles triggers more bypassing behavior due to increased interactions on Lane 1. Subfigures (b) and (d) further reveal that entering vehicles has a more significant impact on bypassing decisions than exiting vehicles. Detailed reasoning can be found in Section \ref{['sec:simulation studies']}.

Theorems & Definitions (6)

• Remark 1: Application Scenarios of Our Model
• Definition 1: Strategic Lane Choice Equilibrium
• Theorem 1: Existence and Uniqueness
• proof
• Remark 2: Steady state is key to obtaining quality data
• Remark 3: Parameter values can reflect intrinsic characteristics of the weaving ramp