## 6 Conclusions  
This study conducts a driving simulation test to examine the effects of roadway characteristics, signage information volume, and traffic circumstances on drivers' car-following and lane-changing behaviors in tunnel-interchange connection sections. The study reveals the following key insights:  
1. Insufficient connection distances negatively impact driver behavior, leading to lower vehicle speed, increased speed variance, and urgent lane-changing maneuvers. Such strong environmental switching from tunnels to interchanges could undermine driving stability and safety, especially when connection distances are shorter than 500 m.
2. Increased signage information loads significantly influence drivers' speed selection, causing an increase in maximum deceleration and following distance. Notably, the velocity reduction amplitude triples when the signage information volume escalates from five to thirteen units. 3. Significant interaction effects are observed between connection distance and signage information volume on car-following behavior. As the connection distance diminishes from 1000 m to 100 m, the average group differences in time headway induced by increased information volume rise by 84.2%, signifying a heightened influence of signage information on driving behavior. 4. Drivers' accepted gap demonstrates a negative correlation with traffic volume and a positive correlation with connection distance. An increase in traffic volume results in a more significant discrepancy in the critical gap acceptance between small spacing and general diverging sections. 5. Based on the critical threshold of behavior index and failure rate, this study suggests that the critical distance of tunnels-interchanges should be 700 m and the sign information should be limited to nine units. For sections with less than 500 m spacing, traffic information should be kept within seven units, complemented by enhanced traffic control in the diverging area. To bolster driving stability and safety in such scenarios, it is essential to maintain the tunnel-interchange distance within acceptable limits, define appropriate signage information volume, and adjust connection clearance according to traffic service level. Consideration of drivers' behavioral traits and traffic conditions is vital in road design and traffic management, contributing to improved road efficiency and safety. This research clarifies the behavioral uncertainty in tunnel-interchange areas and underscores the need for targeted preventive measures from the drivers' perspective. Future work aims to accumulate significant crash samples and traffic conflict data to explore accident mechanisms and latent risks in small spacing sections. Moreover, the growing number of tunnel-interchange project samples paves the way for more extensive on-road driving tests to investigate the impact of dynamic traffic, weather conditions, and other real-world factors on driver workload and behavior. Conceptualization: Z.S., C.G. and W.Z. ; methodology: C.G. and W.Z. ; software: Z.S. ; validation: Z.S., T.X. and J.X. ; formal analysis: T.X. ; investigation: C.G., W.Z., and T.X. ; resources: J.X. ; data curation: C.G. and T.X. ; writing--original draft preparation: C.G. ; writing--review and editing: [PERSON] and W.Z. ; visualization: Z.S. ; supervision: [PERSON] and W.Z. ; project administration: W.Z. ; funding acquisition: J.X. All authors have read and agreed to the published version of the manuscript. This research was supported by the Fundamental Research Funds for the Central Universities, Chang'an University, grant number: 300102212107. Not applicable. The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy. The authors would like to thank [PERSON] and the transportation simulation laboratory of Chang'an University for their support in our study. Author [PERSON] was employed by the company Shaoxing Communications Investment Group Co., Ltd.