## 5 Conclusions  
In this study, we designed three levels of transparency-interface for a specific hazardous event with different urgencies based on the SAT model, and we then evaluated user trust and reliance before and after viewing the interface via NDRT performance and eye gaze duration. Also, takeover performance during driving, as well as subjective trust and workload after driving in different transparency and scenario conditions, were also compared. The most significant finding of the experiment was that transparency has a significant effect on driver trust and reliance on ADS. Presenting SAT level \(1+3\) and level \(1+2+3\) information to drivers resulted in less attention being paid to the driving scenario, higher NDRT performance, and increased subjective trust than did the provision of baseline SAT level \(1\) information. Driver trust and reliance on ADS was higher in the low-urgencythan in the high-urgency scenarios, and driver NDRT performance and attention improved after viewing the SAT information, but not statistically significantly. Thus, it can be concluded that providing drivers with SAT information can increase their trust in and reliance on the ADS, and vehicle's actions and projection information may result in increased trust calibration without increasing the cost of the workload.  
These findings highlight the positive role of the SAT model in human-vehicle interactions and present important implications for the design of automotive HMIs based on the SAT model. In order to achieve a safe and efficient employment of highly automated driving systems, the driver should be provided with transparency information regarding the uncertainty of the vehicle. Developers of ADS should also consider designing HMIs including different transparency and communication channels based on various driving scenarios to improve driver understanding of the vehicle conditions, while minimizing the workload.  
Conceptualization, [PERSON] ([PERSON]) and L.L.; methodology, [PERSON] ([PERSON]); validation, [PERSON] ([PERSON]) and J.L. ([PERSON]); formal analysis, [PERSON] ([PERSON]); investigation J.L. ([PERSON]) and J.L. ([PERSON]); resources, X.W. and J.L. ([PERSON]); data curation, [PERSON] ([PERSON]); writing--original draft preparation, [PERSON] ([PERSON]); writing--review and editing, L.L., X.W. and J.L. ([PERSON]); visualization, [PERSON] ([PERSON]) and [PERSON] ([PERSON]); supervision, L.L.; project administration, [PERSON] and [PERSON]. ([PERSON]); funding acquisition, L.L. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Ethical review and approval were waived for this study since there was no threat to the health and life of the participants. The participants did not take any medications, drugs, or other medical treatments.  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
The authors thank all participants who took part in the study and completed the surveys.  
The authors declare no conflicts of interest.