## 6 Conclusions  
In order to solve the traffic safety problem and improve the transportation system, a V2I-VLC system in typical mountainous road scenarios is studied. In the channel modeling process, the LOS and NLOS links are considered, and propagation characteristics such as AT and other weather factors are included in the system model. In addition, to analyze the performance of the proposed V2I-VLC model, closed-form expressions for the key VLC performance metrics are derived, such as average path loss, received optical power, channel capacity, and outage probability. In order to verify the accuracy of the derived closed-form expressions, Monte Carlo methods are used for stochastic simulation in MATLAB(r) software, version R2023a. Simulation results show that the closed-form expressions have high accuracy and reference values. Unlike existing studies, the effect of NLOS links on the system model is considered more comprehensively, including the NLOS links formed by reflections from mountains and road surfaces. At the same time, a more realistic computational method is used in the consideration of vehicle mobility. In the study of the relevant performance metrics, it can be found that the considered propagation characteristics have a significant impact on the average path loss and received optical power of V2I-VLC. In the LOS link, when \(I_{V_{1}-PD}=50\) m, the difference in channel gain between moderate fog and dense fog versus clear weather conditions is \(1.8\) dB and \(3\) dB, respectively. Additionally, when \(I_{V_{1}-PD}=100\) m, the total received optical power in dense fog conditions is about \(76.2\%\) lower than in clear weather conditions. Furthermore, it is found that transmission distance is a more influential factor than weather conditions in terms of channel capacity and outage probability. In clear weather, the channel capacity at \(I_{V_{1}-PD}=20\) m is about \(87.4\%\) lower than that at \(I_{V_{1}-PD}=10\) m. Similarly, the outage probability increases rapidly as transmission distance increases.  
However, there are some limitations in our study. For example, the effect of neighboring vehicles is not considered in the proposed model. In addition, the channel capacity is not calculated using an exact closed-form expression. In future studies, new techniques can be proposed to minimize the adverse effects of certain propagation characteristics on V2I-VLC systems. Furthermore, the study of the proposed system and modeling revealed that AT and weather conditions are important factors affecting the performance of V2V-VLC systems. The weather conditions considered in the study are clear weatherand fog weather. Therefore, in future studies, the effect of rain or snow weather conditions on the V2V-VLC system can be emphasized. Additionally, other performance metrics applicable to outdoor VLC systems can be further derived.  
Conceptualization, W.Y. and H.L.; methodology, W.Y. and H.L.; software, H.L.; validation, W.Y., H.L. and G.C.; formal analysis, W.Y. and H.L.; investigation, H.L. and G.C.; resources, W.Y. and H.L.; data curation, H.L.; writing--original draft preparation, H.L.; writing--review and editing, W.Y. and H.L.; visualization, H.L.; supervision, W.Y.; project administration, W.Y.; funding acquisition, W.Y. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
**Institutional Review Board Statement**: Not applicable.  
**Informed Consent Statement**: Not applicable.  
**Data Availability Statement**: Data are contained within the article.  
**Conflicts of Interest**: The authors declare no conflict of interest.