## 2 Literature Review
[28] explored the effects of lighting systems on driver behaviour in tunnels, concluding that different lighting conditions can improve safety by enhancing drivers' perception and reaction times. [PERSON] et al. [29] studied the use of retroreflective belts in motorway tunnels and found that these belts provide better visual guidance, improving driving safety. [PERSON] et al. [30] investigated driver fatigue and the fatigue-reducing effects of special lights, concluding that such lights reduce fatigue and improve road safety. A well-designed tunnel entrance presents numerous opportunities for incorporating driving assistance information systems, such as markers and guide signs, to ease drivers' workload while navigating through tunnels. These design elements, along with features like road linearity, width, and shoulders, can enhance safety and efficiency. However, assessing such designs under real-world conditions poses significant challenges. Simulators that replicate tunnel and road designs offer a practical solution, enabling detailed evaluations prior to construction [4]. Simulation testing complements real-world trials by allowing complex and potentially hazardous scenarios to be safely examined [4; 31]. Simulators provide a controlled environment for repeated testing of traffic conditions, minimizing risks while yielding critical insights. Unlike physical tests that may inadvertently create unsafe environments when simulating dangerous scenarios, simulators ensure safety while reducing development costs and enhancing scalability [32]. Consequently, simulators have gained widespread attention among researchers for their ability to consistently and objectively analyze driving performance. Many research studies generate valuable data to improve tunnel safety and inform safer designs for future projects [29]. Advanced driving simulators offer notable advantages, including improved experimental control, cost efficiency, and straightforward data collection [4] However, to produce meaningful results, simulators must undergo rigorous validation [4]. While [PERSON] [25] emphasized the importance of relative validity for simulators to serve as effective research tools, absolute validity is not always essential. Nonetheless, simulators have limitations, particularly in capturing the complexity of real-world conditions, such as human behaviour under stress or fatigue, vehicle dynamics, and environmental factors like weather and traffic congestion. Tunnels are critical components of highways, primarily due to the significant differences in illumination levels between their interiors and exteriors [33]. LED lamps, with a wavelength range of 400-700 nm, closely align with the visible spectrum perceived by the human eye (380-780 nm), resulting in a brighter and more visually comfortable appearance [34]. [PERSON] et al. [28] observed that LED-light tunnels enhanced safety, as evidenced by lower driving speeds and reduced steering efforts when approaching, entering, and exiting the tunnel. These tunnels also facilitated earlier obstacle detection and more controlled avoidance manoeuvres, with drivers reporting greater comfort while navigating through them. Tunnel lighting regulations vary across countries and zones within tunnels, but all guidelines emphasize road surface luminance while neglecting the walls and roof [14]. A common feature in all regulations is the emphasis on road surface luminance, while luminance requirements for walls and roofs are generally absent [14]. The International Commission on Illumination (CIE), through its publication CIE-88, provides standards for safe and comfortable tunnelroads, which are also adopted by Turkiye. According to CIE recommendations, the luminance levels in the inner tunnel areas should range between 1-15 cd/m\({}^{2}\), with a minimum of 3 cd/m\({}^{2}\) preferred to accommodate the extended adaptation period required when transitioning from bright to dark environments [35].