Vehicular communication systems play a pivotal role in modern transportation, offering solutions for traffic management, road safety, and infotainment services. Effective optimization of channel estimation in these systems is imperative to overcome inherent challenges. This paper has explored the issues that hinder reliable and efficient channel estimation in vehicular communications. High mobility and dynamic environments, multipath fading, heterogeneous networks, scalability, and security and privacy concerns were identified as key challenges. Addressing these challenges is crucial for ensuring the robustness and effectiveness of vehicular communication systems. By advancing channel estimation techniques, we can enhance data throughput, reduce latency, and improve overall network performance, ultimately contributing to safer and more efficient transportation systems.