# Temporary Road Marking Paint for Vehicle Perception Tests
## 1 Introduction  
Automated driving systems for highway use cases are increasingly being implemented in road traffic, e.g., in [1, 2]. Compared to country roads, urban areas or rural environments, highway traffic is less complex and yet still provides a high traffic throughput. Within the automotive industry, a challenge for the coming years will be to extend the operational design domain (ODD)--meaning the environmental conditions in which an automated vehicle can safely operate. For automated vehicles relying on onboard sensors to navigate safely through different types of road traffic, their capabilities of detecting and correctly interpreting road markings need to grow. Whereas highways in many parts of the world only possess wide longitudinal markings on straights and in curves that have a big radius, road markings in urban areas are far more complex [3]. Transverse lines are common, longitudinal lines might be narrower, arrows can indicate turning lanes, text and symbols might stipulate certain rules, and rectangular boxes indicate parking slots. The variety and geometric complexity are vast, making it difficult to introduce automated vehicles for door-to-door transportation in cities. To validate and verify the functionality of automated driving systems, vehicle developers utilize proving grounds. A common approach is scenario-based testing, whererepresentative traffic scenarios are created on test tracks [4]. Proving grounds provide isolated, controllable, private test tracks to perform driving maneuvers in a reproducible manner. Since proving grounds only have confined space, some of their operators offer temporary road markings to increase the number of tests that can be conducted on site and to react quickly to customers' demands. According to the IAMTS testbed database [5], at least 14 proving grounds offer a temporary road marking service. Analogous to road markings for road works on highways, this service often utilizes road marking tape. Since the tape is prefabricated, it has a homogenous geometric shape and clear edges and is therefore suitable in terms of reproducibility. Furthermore, it can easily be pressed on the road, allowing comparably low application and removal efforts. The concept described in [6] recommends tape that is homological for use in road works in public traffic and provides a visibility above the minimum requirements for public road traffic [7; 8; 9; 10]. In general, road marking tape is also available for permanent road markings with higher adhesion attributes; however, easy removability is desired for the use case of agile scenario alteration on proving grounds. The advantage of low application effort, which temporary road marking tape has, does not persist for the complex geometric shapes that are often found in urban environments, such as text and symbols. By cutting the tape into fragments of the shape that is required, tape can theoretically be used; however, this process involves significant manual labor compared to using paint and a stencil. In addition, consistent line segments with radii of only a few meters cannot be marked effectively with tape due to its lack of plasticity. A potential solution for the temporary application of complex geometric shapes on proving grounds is removable road marking paint. Figure 1 provides some example use cases. To provide geometrically complex, temporary road markings for perception tests, a specific paint was developed in a collaborative project between Mercedes-Benz and SWARCO. The paint was required to maintain good, constant visibility over the course of a test drive, which usually has a duration of up to four weeks. Ideally, the road marking paint should not be affected by precipitation. Regardless, it should be easily removable without residuals or other traces. Lastly, the paint should be cost-effective and environmentally compatible. Multiple samples with different material properties were manufactured and tested at the Mercedes-Benz Technology Center (MTC) in Immendingen, Germany.