SMART MOBILITY |
Ma(r)king roads readable for self-driving cars For safe and efficient deployment of self-driving vehicles to become a reality, we first need lane markings and road signs that can be read easily by cameras and sensors Words | Richard Neumann, Swarco, Austria
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AV, V2X, C-ITS, CCAM – the acronyms differ, but they all have one thing in common. They all represent a connection between road infrastructure and vehicles that aims to improve traffic flow, reduce emissions, make traffic safer and make our journeys more convenient. Vehicle automation is often cited as one of the biggest disruptive technologies, both economically and environmentally. But for automation to happen, the surrounding infrastructure must be adapted to support efficiency and safety. Connected infrastructure is key to design and certification procedures as well as for testing environments. Connectivity between infrastructure and vehicles is also necessary to support operational conditions in the transition period, which could last for decades. Apart from the automotive and C-ITS aspect of managing the traffic of self-driving cars, it is also essential to consider the road itself, and in particular its readiness to be read by driver assistance technologies. “Lane markings are currently read by two kinds of sensors: camera and lidar,” says Harald Mosböck, Swarco’s vice president of road marking systems for Europe and the APMEA regions, and vice president of the European Union Road Federation (ERF). “Even the most advanced vehicles equipped with high-definition maps need sensors to capture information from lane markings and traffic signs, and to determine whether all the data fits together. Road markings and traffic signs still lack uniformity on roads.
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There are too many differences. And for as long as these things remain inconsistent, we will not be able to fully rely on sensors.”
Global initiative
On an international level, it is mainly the Japanese, American and European standardization bodies pushing to improve and standardize road markings. The latest edition of the North American Manual Commission to on Uniform Traffic The number of form an expert Control Devices different weather group to work (MUTCD) is conditions in which out how to make to contain a road markings requirement for Swarco has tested and traffic signs major roads that lane markings easily readable for normal lines be vehicles and, of 150mm (6in) wide and course, for humans for markings to be more as well. Initial results were uniform. Just recently, a major expected by mid-2021 but, due to standardization body proposed to the COVID-19 pandemic, will not the Federal Highway Administration be available before spring 2022. (FHWA) that lane markings on the “In general we can say the future highway network should not communication between carmakers, only have a standardized width, industry associations and Brussels on but there should be a general the expectations for the quality of requirement for dotted lines at road markings has already greatly highway exits and a standardized improved,” says Mosböck. gap width for interrupted lines. One recommendation pushed Right now, there is work in progress forward by the European Road addressing the topic of better Federation (ERF) is very similar to retroreflectivity, which is a very the approach in the USA. The challenging subject. Another issue formula was created based on what is how lane markings in roadwork the human eye can see, with the goal zones can be improved to attain to improve road safety. Interestingly, reliable and consistent machine several studies show that what is readability for automated or good for the human eye also works assisted driving. very well for machine vision. The In 2019, the European Council 150 x 150 formula recommends revised its road safety management a line width of 150mm and a directive and charged the European
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