Visible Light Communication (VLC) has recently emerged as an alternative to RF-based wireless communications. VLC for vehicles has demonstrated its potential for Intelligent Transportation Systems (ITSs) to exchange information between vehicles and infrastructure to achieve ITS core goals, such as improving road safety, passenger comfort, and traffic flow. This paper seeks to provide a detailed survey of vehicular VLC systems. This paper presents an overview of current developments in vehicular VLC systems and their benefits and limitations for experienced researchers and newcomers.

This paper provides a comprehensive study to investigate the potential of multi-relay methods in V2V-VLC systems through detailed performance analysis using realistic channel modeling based on ray tracing. Key performance metrics evaluated include maximum achievable communication distances, system capacity, and the influence of system parameters, transceiver design, and environmental factors, such as fog and rain. Results demonstrate that adverse conditions, such as thick fog, can reduce the direct communication range by up to 19.5% at high transmission power (P_t = 25 dBm), limiting it to 33 m. However, incorporating multi-relay links significantly extends the transmission range, reaching 140 m under thick fog conditions and up to 170 m in clear weather with three relays. Additionally, analysis shows that increasing the receiver aperture diameter enhances the system’s maximum achievable range, with a 4 cm aperture enabling distances up to 700 m in a multi-relay setup. Furthermore, the study highlights that increasing the number of relays improves system capacity, achieving up to 358 m at 5 Mbit/s with seven relays under clear atmospheric conditions. These findings underscore the importance of multi-relay strategies in improving the reliability and effectiveness of V2V-VLC systems across diverse operating scenarios.