Manual Drivers' Evaluation of Automated Merging Behavior in Dense Traffic: Efficiency Matters

The vision to integrate automated vehicles into manual traffic motivates to investigate automated merging in dense traffic. To gain an easy, distinct and interpretable behavior for interacting traffic this study investigates release conditions of lane changes into small gaps in a within-subject design on a test track with 39 participants. To generate standardized situations all merging maneuvers are performed automatically. The study is divided into two parts. In the first part participants validate different times headway between the participant's vehicle and automated vehicle under different situational parameters (deceleration to target gap, velocity and existence of road work). In the second part, participants release the lane change of the automated vehicle themselves, when they expected it to merge. Here, in addition to part one, the automated vehicle adjusted velocity to the target gap with weak and strong deceleration. The results show that participants prefer an efficient lane change of the automatic vehicle, where interacting traffic has to react as little as possible. Compliance with safety distances is not decisive. The required times headway between automated and interacting vehicles decreases with higher velocity and in lane narrowing situations. The study contributes to the design of vehicle behaviour that can enhance the acceptance of automated vehicles in mixed-traffic.