Effectiveness of smart horizontal markings on drivers' behavior along horizontal curves: A driving simulation study

Photoluminescent road markings (PRMs) are a potentially useful visual guidance technology for improving road safety in low-visibility conditions. However, the effectiveness of PRMs requires further research. Moreover, road infrastructure regulations lack guidelines for PRMs design. Here, we aimed at determining the effects of different PRMs colors and widths on transversal and longitudinal driving behavioral indices. We conducted a simulation-based 3x2x2 within-subjects experiment (PRM: unlit vs. smart green vs. smart red; marking width: conventional vs. wide; curve direction: left vs. right). We designed six two-lane rural highway scenarios with nighttime light conditions and no traffic. Each scenario included twenty-four horizontal curves with radii ranging from 120 to 440 m (recommended speed range 60-90 km/h). Thirty participants (age range 20-54 years) drove a semi-dynamic driving simulator for about one hour. Our results showed that the presence of PRMs affected the drivers' transversal behavior. The smart markings induced drivers to keep greater lateral distances from the road edge line than unlit ones along right curves. Smart green markings showed higher variability for vehicle positioning, indicating lower vehicle control. Wider-than-normal markings induced users to drive closer to the edge line at the Tangent-to-Spiral section. Overall, our study showed that smart markings - both green and red - induce the driver to "shy away" from the edge line, thus representing a potential tool for preventing roadway departure events. Further studies are expected to confirm these results by focusing on different PRM layouts, traffic, and weather conditions.