In mixed traffic environments that involve conventional vehicles (CVs) and autonomous vehicles (AVs), it is crucial for CV drivers to maintain an appropriate level of situation awareness to ensure safe and efficient interactions with AVs. This study investigates how AV communication through human-machine interfaces (HMIs) affects CV drivers' situation awareness (SA) in mixed traffic environments, especially at intersections. Initially, we designed eight HMI concepts through a human-centered design process. The two highest-rated concepts were selected for implementation as external and internal HMIs (eHMIs and iHMIs). Subsequently, we designed a within-subjects experiment with three conditions, a control condition without any communication HMI, and two treatment conditions utilizing eHMIs and iHMIs as communication means. We investigated the effects of these conditions on 50 participants acting as CV drivers in a virtual environment (VR) driving simulator. Self-reported assessments and eye-tracking measures were employed to evaluate participants' situation awareness, trust, acceptance, and mental workload. Results indicated that the iHMI condition resulted in superior SA among participants and improved trust in AV compared to the control and eHMI conditions. Additionally, iHMI led to a comparatively lower increase in mental workload compared to the other two conditions. Our study contributes to the development of effective AV-CV communications and has the potential to inform the design of future AV systems.

翻译：在涉及传统车辆（CV）与自动驾驶车辆（AV）的混合交通环境中，确保CV驾驶员保持适当的情境意识水平对于与AV安全高效交互至关重要。本研究探究了通过人机界面（HMI）进行AV通信对混合交通环境中CV驾驶员情境意识（SA）的影响，尤其聚焦于交叉口场景。首先，我们通过以人为本的设计流程设计了八种HMI概念，并选取评分最高的两种概念分别实现为外部和内部HMI（eHMI与iHMI）。随后，我们设计了一个包含三种条件的被试内实验：无任何通信HMI的控制条件，以及分别使用eHMI和iHMI作为通信手段的两种处理条件。在虚拟现实（VR）驾驶模拟器中，我们考察了这些条件对50名充当CV驾驶员的参与者的影响，并采用自我报告评估与眼动追踪测量来评价参与者的情境意识、信任度、接受度及心理负荷。结果表明，与控制条件和eHMI条件相比，iHMI条件显著提升了参与者的SA水平及其对AV的信任度。此外，iHMI条件下心理负荷的增加幅度相对低于其他两种条件。本研究有助于发展有效的AV-CV通信机制，并为未来AV系统的设计提供参考。