Research in MAC (Medium Access Control) protocols for Vehicular Ad Hoc Networks (VANETs) focuses on designing efficient, adaptive, and collision-free channel access mechanisms to support high-speed vehicle communication and dynamic topology changes. Recent studies introduce hybrid MAC protocols that combine contention-based and TDMA-based schemes to achieve low latency and high throughput in both dense urban and sparse highway environments. Machine learning and reinforcement learning techniques are increasingly applied to predict traffic density, optimize channel allocation, and enhance QoS provisioning. Priority-aware and context-sensitive MAC protocols are also developed to ensure reliable transmission of safety-critical messages with minimal delay. Additionally, energy-efficient, blockchain-assisted, and edge-enabled MAC frameworks are being explored to improve scalability, fairness, and security. These advancements collectively enhance communication reliability, reduce packet collisions, and ensure real-time performance in next-generation VANET systems.