### Elements of Novelty in This Article  
In light of the above, this article provides an analysis concerning the usage of the VLC technology in communication-based vehicle applications. Unlike most of the existing works on this technology, the present article addresses two of the most unfavorable use cases. First, instead of investigating the usage of a rather high power optical source, like a traffic light [21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31] or a vehicle headlamp system [32], this work investigates the capabilities of a VLC system based on LED rear lamps; this approach involves a significantly lower optical power. Secondly, this article also explores the effect of vehicle misalignment on the performances of a V2V VLC link. In this scope, a VLC test bench has been designed and implemented as a prototype, in order to experimentally investigate the possible communication distance of a V2V system, and also to use it in an experiment-centric approach in one of the unfavorable scenarios of vehicles misalignment, namely the one where the two vehicles are located on different lanes. To maintain a realistic approach and to ensure that the results are in accordance with the real-world conditions, the light distribution pattern of some existing commercial vehicles has been analyzed and compared to the light radiation pattern of the proposed VLC emitter. Next, the V2V VLC prototype has been used to recreate the scenario and to experimentally determine the performances of the V2V VLC link in two cases: one with the vehicles on the same lane and one with vehicles on adjacent lanes. In the end, the minimum communication distance, the achievable communication range and the Bit Error Ratio (BER) have been experimentally determined. The final results demonstrated a record V2V communication range of up to 75 m and BERsas low as \(10^{-7}\) without the use of forward error correcting protocols. Thus, one can see that this article follows a highly realistic approach, analyzing less favorable situations, and more than this, it demonstrates improved performances with respect to the existing literature addressing vehicular VLC applications. This article continues the work started in [33], providing an in-depth theoretical and experimental analysis concerning the use of VLC technology in V2V applications. Unlike [33], which provided limited results valid only in night conditions, this article provides an exhaustive theoretical analysis, the intensive day testing demonstrating the effect of an adequate front-end block, together with improved results in terms of communication distance and BER performances. Furthermore, this article also provides a comparison between the results achieved in night conditions and in day conditions along with a comprehensive discussion concerning the future of VLC in automotive applications.  
The rest of this article is organized as follows. Section 2 provides a summary concerning the progress of vehicular VLC applications. Section 3 presents an analysis concerning the influence of the incidence angle on the quality of the vehicle-to-vehicle visible light communications link. Section 4 describes the experimental setup for the vehicle rear lighting system irradiance determination and presents the results showing the irradiance pattern of two commercial vehicles. Section 5 provides the description of the VLC prototype that was used for the experimental tests, whereas Section 6 describes the outdoor testing procedure. Section 7 delivers the experimental results, followed by Section 8, which provides a discussion on the results and emphasizes the contributions of this work. Finally, Section 9 ends this article by summarizing the conclusions of this work.