Road markings in the age of automated driving

Seeing with the machine eye

Machine vision works differently than the visual perception of human road users. Friedrich Wiesinger, Team Leader of Product Development at SWARCO Road Marking Systems, nevertheless sees certain similarities between camera-based systems for automated driving and the human eye based on the research results: "Our research has shown that cameras perceive road markings as well or as poorly as the human eye. Especially in bad weather or difficult lighting conditions, the eye and camera both have their limitations. But this is precisely when high-performance markings can support both man and machine." 

LiDAR resists the glare

Drivers are particularly familiar with the difficulty of recognizing road markings when the sun is low or the light from oncoming traffic is causing glare. While this is also a problem for camera-based systems, automotive LiDAR sensors (LiDAR = Light Detection and Ranging) cope better in these situations. This is an important finding from various tests carried out by the Center of Competence. However, further investigations show that LiDAR also has difficulty detecting ground markings in the rain. "As long as the drop-on beads of markings remain above the water surface, the headlight light is reflected back or the laser pulse is reflected by LiDAR and the marking can be detected," explains Wiesinger, also pointing out the advantages of high-performance markings in this context. For example, the drainage effect of textured markings allows water to run off and the marking remains visible for much longer in rain.

The glass bead is the key

In numerous tests, the CoC team and its partners from research and industry are investigating the differences between standard beads and SWARCO SOLIDPLUS & SWARCO DURALUX premium reflective glass beads. "In general, almost all studies have shown that the quality of the glass beads used is a decisive factor," Wiesinger points out an important point. With premium glass beads, for example, road markings can be detected early by machine systems. This time advantage enables vehicles to calculate routes more reliably and increases road safety.

In some countries around the world - for example in the USA and China - legal regulations have already been put in place for the traffic of the future. In Europe, on the other hand, there is currently little movement, as Friedrich Wiesinger also has to acknowledge: "It is a pity that the efforts of the European Union to set uniform standards for road markings on the trans-European road network are currently on hold. Particularly given the fact that vehicles will have to be mandatorily equipped with lane departure warning systems from this year onwards. After all, drivers should be able to use these systems in the best possible way."

Nevertheless, the CoC team and its partners are continuing their research this year into how lane markings can be better detected by sensors in order to increase the reliability of the systems. This is why Friedrich Wiesinger is looking to the future with confidence: "2024 will definitely be an exciting year!"