# Temporary Road Marking Paint for Vehicle Perception Tests
## 2 Related Work  
A literature review was conducted using the search engine Google Scholar. Only English and German literature was screened since the literature regarding automated driving and road traffic infrastructure is predominantly published in these languages. The tags used were \"temporary road marking\", \"temporary road marking paint\", and \"proving ground road markings\". Further relevant literature was identified through the reference lists of thematically relevant articles. Road markings are common on public roads and regarded as a basic low-cost safety measure [12]. The relationship between road markings and automotive sensors is increasingly being investigated in the fields of automotive and civil engineering. Many recent studies in this context focus on the improvement of sensor technology to correctly detect and classify valid road markings--see, e.g., [13; 14; 15]. Since longer periods with a mixed traffic environment are expected, during which automated vehicles and human-driven vehicles share the roads [16], road markings need to possess high visibility for machine as well as human vision. The authors of [17] point out that specifications for road markings that are highly visible for humans can be transferred to facilitate high visibility for machines, too. According to [18], the recognizability of road markings through machine vision is dependent on the sensor system itself and the road markings' retroreflectivity, structure, and color, and the type of glass beads used. The attributes of road markings change over time due to weather and overruns. Proper and frequent maintenance can support a constant and high visibility. To identify renewal demands, machine vision can be used [19]. Increasing numbers of vehicles equipped with machine vision can therefore present an opportunity for more efficient maintenance concepts and a generally improved road marking quality on public roads. Next to the long-term effects weather has on the visibility of road markings, lighting and road conditions (wet/dry) correlate with visibility [20]. Besides optical attributes, uniformity and standardization are expected to positively contribute to accelerating the performance improvements of automotive sensor systems that are intended for recognizing road markings [21]. The impact of the agile alteration of road markings on the number of tests of automated driving systems on proving grounds was revealed through two previous studies. An expert survey conducted in 2020 revealed the need for road markings that are easy to apply and remove for flexible scenario generation [22]. In addition, ref. [6] revealed that approximately one-quarter of road vehicle tests in published protocols from certifications, ratings, and standards have specifications for road markings. The published literature on the use of temporary road markings for vehicle and sensor tests on proving grounds is scarce; however, articles investigating temporary road markings in general or for the use case of traffic control in construction zones were found. Commonly, either removable paint or tape are used. For temporary road markings, as well as for permanent road markings, visibility is crucial in both daytime and nighttime. To increase the reflectivity of the markings, especially at night, retroreflective beads can be used [23; 24]. The requirements for temporary road marking paint relate to the visibility, removability, durability, and environmental compatibility of the material. The challenge in using road marking paint lies in being able to remove it completely without any residue on the road surface [25]. Removability and durability are partly perceived as conflicting objectives [26]. For temporary road marking paint, environmental compatibility is especially crucial since the removal process usually involves a liquid for dissolving the paint that drains into either a sewage system or adjacent nature [ibid.].