## 1 Introduction  
Visible light communication (VLC) is a wireless communication technology that marks significant progress in recent years towards reliability, security, and efficiency, ensuring the transition from an emergent to a confirmed technology. VLC uses the visible light spectrum of solid-state light (SSL) devices not only for illumination, but also for simultaneous data transmission purposes [1], resulting in numerous advantages, such as energy consumption efficiency, an unprecedented bandwidth, and a never-before-imaginable pervasive spread potential throughout various domains. Based on such a high potential, VLC has been found to be appropriate for numerous applications, from high-data-rate indoor applications [2] to underwater communication [3], and more recently, for Internet of Things applications [4]. Moreover, VLC is capable of having a major impact on the development of 6G-and-beyond technologies [5, 6]. In addition, intensive research efforts have demonstrated that VLC can provide high-precision positioning [7], opening the path for a multitude of new applications. Last, but not least, VLC has been found to be suitable for various environment-sensing applications [8; 9; 10; 11]. Thus, one can see that VLC evolved from the point of being seen only as a possible technology, to the point where light sources became capable of wireless communication, range measurements, high-precision positioning, and obstacle detection, up to the point where it can provide a basis for the integrated communications and sensing (ICS) concept. A particular use for VLC is for communication-based vehicle safety applications [12; 13; 14]. In this area, VLC is favored by the wide integration of SSL sources as part of vehicle lighting systems, and also as part of the transportation infrastructure, such as traffic lights, traffic signs, information display panels, and street lighting systems. Thus, the wide distribution of SSL-based sources, as well as their relatively high optical intensity, makes the vehicular use of VLC one of the most relevant and straightforward application scenarios. Moreover, the use of VLC in inter-vehicle communication is a complementary and fully compatible alternative to the traditional radio-frequency (RF) communication systems, augmenting its performance in terms of the resilience to interference and jamming attacks, ensuring lower latencies, and providing higher packet delivery ratios [12; 15; 16; 17]. Despite the fact that this was the first domain of utilization for VLC technology, the characteristics of the outdoor channel raised numerous challenges [12]. It should be remembered here that the vehicular VLC channel is characterized as being highly dynamic and unpredictable, subject to numerous optical noise sources, and influenced by weather phenomena, such as fog, rain, and snow, which affect the passage of light, worsening the signal-to-noise ratio (SNR) [18]. Regardless of these unfriendly conditions, VLC has made impressive progress, achieving a performance that was difficult to imagine before. Thus, today's vehicular VLC prototypes can provide a high resilience to optical interference [19; 20; 21], including the interference generated by multiple VLC transmitters [22]; decent data rates; and communication ranges of up to almost 200 m [23], indicating that this technology is almost ready for real-life implementation [24; 25; 26]. Although substantial strides have been made in advancing vehicular VLC technology, its specific challenges require further research efforts. Thus, improving the vehicular VLC resilience to noise and optimizing the compatibility with dynamic mobile conditions still remain the most important research demands [12]. From this perspective, the vehicular environment poses unique challenges, including low optical power data signals with a high potential for interference from various optical sources, inconsistent ambient lighting, and vehicle motion.