Merging in a Coupled Driving Simulator: How do drivers resolve conflicts?

TL;DR

This study uses a coupled driving simulator to analyze how initial vehicle kinematics influence merging outcomes and reveals that drivers rely on key decision moments and intermittent control rather than continuous optimization.

Contribution

It introduces an experimental approach to study merging behavior with controlled initial conditions and highlights the role of intermittent control in driver decision-making.

Findings

Kinematics can predict merging order and conflict duration.

Drivers use key decision moments with intermittent control during merging.

Results support models based on piecewise-constant control.

Abstract

Traffic interactions between merging and highway vehicles are a major topic of research, yielding many empirical studies and models of driver behaviour. Most of these studies on merging use naturalistic data. Although this provides insight into human gap acceptance and traffic flow effects, it obscures the operational inputs of interacting drivers. Besides that, researchers have no control over the vehicle kinematics (i.e., positions and velocities) at the start of the interactions. Therefore the relationship between initial kinematics and the outcome of the interaction is difficult to investigate. To address these gaps, we conducted an experiment in a coupled driving simulator with a simplified, top-down view, merging scenario with two vehicles. We found that kinematics can explain the outcome (i.e., which driver merges first) and the duration of the merging conflict. Furthermore, our results show that drivers use key decision moments combined with constant acceleration inputs (intermittent piecewise-constant control) during merging. This indicates that they do not continuously optimize their expected utility. Therefore, these results advocate the development of interaction models based on intermittent piecewise-constant control. We hope our work can contribute to this development and to the fundamental knowledge of interactive driver behaviour.