Examining the Impact of different LED road Studs Layout on Driver Behavior along Horizontal Curves at night-time

Driving at night poses serious road safety issues due to reduced visibility, increased risk of fatigue, and greater likelihood of encountering impaired or distracted drivers. Improving road visibility in the absence of adequate lighting systems, can effectively improve safety. Literature confirms that active road studs have emerged as a potential solution to address the associated challenges. However, the optimal layout for achieving the greatest improvement in driver behavior and road safety remains unclear. This study aims at assessing whether the change in layout of the road studs on a two-lane rural highway can improve drivers’ performance in night-time driving. The experiment was carried at the driving simulator of the Road Safety and Driving Simulation Laboratory of Politecnico di Torino. Thirty-five participants were involved in the experiments. Five different LED stud layouts were investigated: (i) unlit, (ii) only centerline, (iii) at the lane edges, (iv) at the carriageway edges and (v) both at the centerline and carriageway edges. These conditions were evaluated along curve with different radii (i.e., 120, 210, 300 and 440 m) and direction (i.e., left vs. right). In addition, we evaluated the drivers’ gaze behavior with an eye tracking system to understand what element the driver used to manage the lateral control. We used the repeated measures ANOVA to evaluate the impact of layouts and other experimental variables on longitudinal and transversal behavior of participants. We found that the LED stud layout significantly affected driver behavior along curves of different directions. For right-turn curves, road studs at the carriageway edges (configuration iv) significantly improved driver behavior. For left-turn curves, the best layout was with studs at the lane edges (configuration iii). These outcomes highlight that the curve direction strongly influences driver behavior. Regarding gaze behavior, the results showed that the visual strategy used by drivers was not only affected by LED layout but also on curve direction, radius, and individual behavioral habits. This study recommends installing the LED studs at the lane edges to ensure optimal driving performances for curves of both directions. This recommendation is also applicable to right curves since the impact of condition (iii) lane edges and (iv) carriageway edges are only slightly different. However, such evidences do not account for costs. Therefore, further studies should examine the impact of the LED road studs layout considering both road safety and economic implications.