## 5 Conclusions  
The study investigated the impact of four low-cost road marking interventions on driver behavior in horizontal curves with sharp (125 m) and wide (350 m) radii. The road marking interventions were continuous red and red-white patterns on edge road markings, an alternating red-white checkered median stripe, and red dragon's teeth, all accompanied by a vertical warning sign 150 m before the curve. These interventions prompted drivers to reduce their speed before entering the circular curve. Drivers decreased their speed at a rate similar to the control condition before the curve began. They continued to slow down until the vehicle gradually passed the transition curve. The dragon tooth condition had the highest reduction in speed in the transition curve, but the effect faded away when vehicles reached the middle of the curve. This was because this particular intervention was implemented before the curve. In the RWE condition, the lateral position of the vehicles tended to shift toward the center of the road. Additionally, in the RE condition, the lateral movement remained similar, closer to the road's centerline, and leaned towards the centerline at the end of a sharp curve. These treatments could serve as a beneficial countermeasure for horizontal curves where run-off-road crashes are a concern. Conversely, the RWM treatment significantly impacted the lateral position before and during the curve, moving the vehicle closer to the edge of the road. Moreover, the RDT treatment influenced the lateral position to a lesser extent, with the car moving closer to the centerline at the beginning of the transition curve before drifting further away upon reaching the midpoint. Overall, the study reinforces the potential of cost-effective road design interventions in improving driver behavior in hazardous horizontal curves. However, these countermeasures and road markings are not universally effective, and their impact varies with curve radius, direction, and position along the curve. By optimizing lateral position, these markings could reduce lane departure crashes, especially if tailored to specific curve types. Implementing such perceptual markings can be an alternative or complementary measure to traditional road safety strategies, particularly in rural road settings where infrastructure modifications may be impractical or costly. This study demonstrates that perceptual road markings (RE, RWE, RWM, RDT) reduce speeds and adjust lateral positioning in horizontal curves, enhancing safety. RE and RDT are most effective for speed reduction, while RWM optimizes lane position. The study was conducted in a controlled simulator, so it does not account for real-world variables like traffic density, driver distractions, or road surface variations, all of which could influence driver behavior. In addition, while highly effective for controlled experiments, driving simulators have inherent differences from real-world road environments. Factors such as driver perception, vehicle dynamics, road surface conditions, and environmental influences (e.g., lighting, weather, and traffic interactions) may vary between simulation and real-world scenarios. Based on the research findings, it is recommended to install perceptual road markings, such as RE and RDT, on horizontal curves with high crash rates, especially those with sharper turns. These markings have been shown to reduce driving speeds, lowering the risk of crashes in dangerous areas. Focusing on high-risk spots makes the best use of limited resources. In addition, running pilot programs and field trials in different areas and traffic conditions can demonstrate how well these markings work outside of simulations. Real-world tests ensure the markings perform well under various conditions, like bad weather or heavy traffic, and help confirm their value. In future research, the authors plan to extend simulations by incorporating varying weather conditions and time-of-day factors to validate the proposed designs more comprehensively.