Dark and wet road conditions and glare – even in difficult circumstances, SWARCO Road Marking Systems’ high-performance markings can be detected by cameras and LiDAR sensors. The visibility and detectability of road markings play an essential role in autonomous driving. Together with ZKW Group, SWARCO Road Marking Systems tested the detectability of different marking systems by vehicle sensors in challenging road conditions. The high-performance marking system demonstrated its strengths in each of the test situations.
Modern driver assistance systems depend on clearly visible road markings. Dark and wet conditions, as well as headlight glare from oncoming traffic continue to represent challenging situations. They require clearly detectable marking systems that can be recognized by vehicle sensors even in adverse conditions. This is of great importance for the development of advanced driver assistance systems and automated vehicles. The better road markings are detected by cameras and LiDAR sensors, the safer road transport is for humans and machines.
For this reason, SWARCO Road Marking Systems together with experts from ZKW Group, a specialist in innovative premium light systems and electronics for vehicles, tested two different road marking systems.
The night tests were conducted at the Digitrans test center for automated driving in St. Valentin, Austria. For this purpose, a pedestrian crossing was applied using two different marking systems: one half had a plain marking system with standard glass beads, while on the other half, a high-performance system was applied using structured markings with SWARCO SOLIDPLUS premium reflective glass beads. To simulate wet conditions, the entire pedestrian crossing was placed under water several times in the course of testing. Glare from oncoming traffic was also part of the test scenarios, with the cameras and LiDAR sensors of the ZKW test vehicle targeting the different markings. The recorded data was then analyzed and assessed.
The analysis showed marked differences in the detectability of the marking systems in dark and wet road conditions with glare. Under these special circumstances, the high-performance system demonstrated its strengths, making a compelling case: According to the recorded data, the test marking was detected by both the cameras and the LiDAR sensors in all test scenarios. The structured marking used in the high-performance system created a drainage effect, allowing for the water to run off more quickly. Therefore, the measured values never fell below the threshold value relevant for detection, and the test marking remained detectable for the sensors at all times. Another decisive factor was the excellent retroreflection of the SWARCO SOLIDPLUS premium reflective glass beads.
In comparison, the LiDAR sensors were, at times, no longer able to detect the plain marking in wet conditions, independent of glare. Tomasz Burghardt, in charge of Project Management R&D at SWARCO Road Marking Systems, explains: “Structured markings are better at draining the water, allowing for the glass beads on the surface to protrude from the water film. As a result, when it’s dark and rainy, the visibility of high-performance markings is significantly better compared to that of plain markings – both for humans and machines. The slightly higher refractive index of SWARCO SOLIDPLUS glass beads also contributes to this.”