## 6 Conclusions and Suggestions  
This study aimed to explore the impact of different tunnel lighting scenarios on driver behaviour, particularly lane-changing behaviours, using a driving simulator on the route including the \"Zigana Tunnel\" in Turkiye. The findings highlighted the influence of various tunnel lighting configurations on driver speed, lane utilization, and lane-changing behaviour under virtually simulated conditions. The results demonstrated that tunnel lighting significantly affects driving performance, with scenarios involving red and flashing red lights prompting greater caution, reduced speeds, and safer lane-changing behaviours. In the study, Lane-Changing Behaviour (LCB) of drivers for three suggested tunnel scenarios are also examined using the data obtained from the driving simulator. For this purpose, all parameters which have an effect on LCB were investigated using a probit regression model (PM) for all scenarios. The following key conclusions were obtained:  
* The study found that drivers tend to reduce speed in tunnel sections with red and flashing red lights, as these signals indicate potential danger. Conversely, green lights encouraged higher speeds, signalling a safer environment for continued driving. S-3, which involved flashing red wall lights and lane closures, proved most effective in reducing driver speed and ensuring safer lane-changing behaviours. * Drivers exhibited different LCBs depending on the scenario. In S-1, where blue sky lighting was used to reduce stress without presenting obstacles, lane-changing was less frequent. However, in S-2 and S-3, which introduced stopped vehicles and lane closures, drivers performed more lane-changings in response to hazardous conditions. * The analysis of driver demographics and experience revealed that female drivers and those with prior simulator experience were more likely to perform safer lane-changings. Additionally, more experienced drivers tended to select the appropriate lane earlier, reducing the need for frequent lane-changings in hazardous conditions. * The study also demonstrated that drivers with higher self-assessed driving skills and more aggressive profiles were more likely to change lanes frequently, aligning with previous research on driver behaviour in challenging environments. Meanwhile, drivers who rated their abilities as lower were more cautious and likely to switch lanes in anticipation of hazards. * When analysing the total number of entry and exit lane-changings in all scenarios, it was observed that there were more lane-changings in the exit zone (N = 134) (with green lighting) than in the entry zone (N = 124). This result shows that after exiting the dangerous tunnel sections, people feel relaxed by the green lights and tend to continue their journey in the lane they consider safest. Based on the findings of this study, the following recommendations are proposed to enhance tunnel safety and optimize driving behaviours in tunnel environments:
* Implementing dynamic tunnel lighting systems, such as the red and flashing red lights tested in this study, can effectively alert drivers to potential hazards and encourage safer driving behaviours. These systems should be considered in the design and retrofitting of tunnel infrastructure, particularly in high-risk sections. * The positive effect of previous simulator experience on LCB suggests that incorporating driving simulators into driver education programs could enhance drivers' ability to respond appropriately to hazardous tunnel conditions. Training programs focusing on tunnel safety and lane selection strategies should be developed. * In addition to lighting, clear and early signage within tunnels can further guide drivers in making safe lane-changings. Integrating visual cues such as flashing lights with clear signage can improve overall driver response, particularly in long tunnels with frequent traffic disruptions.