Data underlying the publication: Designing User Interfaces for Partially Automated Vehicles: Effects of Information and Modality on Trust and Acceptance

This study aims to identify how user interfaces (UI) can enhance driver's trust and acceptance and reduce perceived risk. Four interfaces were designed with different levels of complexity. These levels were achieved by combining automation information (surrounding information vs surrounding and manoeuvre information) and modality (visual modality vs visual-auditory). These interfaces were evaluated in a driving simulator in which a partially automated vehicle reacted to an event of a merging and braking vehicle in its front. The criticality of the events was manipulated by the factors merging gap (in meters) and deceleration (m/s2) of the vehicle in front. This reaction of the automation was either to brake or to change lanes. The results show that an optimal combination of automation information and modality enhances drivers' trust, communication with automation, perceived ease of use, and perceived usefulness. More specifically, the most complex UI, which provided surrounding and manoeuvre information via the visual and auditory modalities, was associated with the highest trust and acceptance ranking and the lowest perceived risk. Manoeuvre information delivered through the auditory modality was particularly effective in enhancing trust and acceptance. The benefits of the UIs were consistent over events. However, in the most critical events drivers did not feel entirely safe and did not trust the automation completely. This study shows that the design of UIs for partially automated vehicles should include surrounding and manoeuvre information combining visual and auditory modalities.

本研究旨在探究用户界面（User Interface，UI）如何提升驾驶员对自动化系统的信任与接受度，并降低其感知风险。本研究设计了四类复杂度各异的用户界面，其复杂度通过组合自动化信息类型与交互模态加以调控：自动化信息类型分为仅周边信息、周边与操作信息两类；交互模态则分为视觉模态、视觉-听觉模态两类。上述界面均在驾驶模拟器中开展评估，测试场景为半自动化车辆对前方正在并入车道并制动的车辆做出响应；测试事件的临界程度通过两项参数调控：前方车辆的并入间距（单位：米）与减速度（单位：米每二次方秒），且半自动化系统的响应动作分为制动与变道两种。研究结果表明，自动化信息类型与交互模态的最优组合可显著提升驾驶员对系统的信任度、与自动化系统的交互流畅性、感知易用性与感知有用性。具体而言，通过视觉-听觉模态同时呈现周边信息与操作信息的高复杂度用户界面，获得了最高的信任度与接受度排名，同时感知风险最低；通过听觉模态呈现的操作信息，对提升驾驶员信任度与接受度的效果尤为显著。各类用户界面的优势在所有测试事件中均保持一致，但在临界程度最高的测试事件中，驾驶员仍未获得完全的安全感，也未能完全信任自动化系统。本研究证实，半自动化车辆的用户界面设计应纳入结合视觉与听觉模态的周边信息与操作信息呈现方案。