## 1 Introduction  
The rapid increase in the number of vehicles on the road in recent years has led to severe traffic congestion and a corresponding rise in transportation-related accidents. These challenges have become a major concern for governmental and transportation authorities worldwide [1; 2]. Expanding road infrastructure is no longer a practical solution due to growing land constraints and the escalating costs of construction and maintenance [3; 4]. In response to these limitations, Vehicular Communication Networks (VCNs) have emerged as a promising alternative, attracting significant attention from governments, industries, and the research community [5]. VCNs enable real-time communication and data exchange between vehicles, aiming to reduce traffic incidents, enhance road safety, and improve overall traffic efficiency while also supporting infotainment services [6]. According to the United States Department of Transportation (USDOT), such intelligent vehicular systems have the potential to reduce road collisions by up to 82% through timely warnings and improved situational awareness. Key safety functionalities provided by VCNs include intersection collision alerts, emergency vehicle proximity warnings, road condition updates, and post-crash analysis systems [7]. The architecture of VCNs is typically composed of two core components: Roadside Units (RSUs) and On-Board Units (OBUs). These components are embedded with smart communication and positioning systems that allow vehicles to exchange information and support intelligent decision-making in real time [8]. Communication in VCNs takes place across three major types: Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), and Infrastructure-to-Infrastructure (I2I) links. These modes are illustrated in Figure 1, offering a holistic view of the VCN communication framework [9]. The communication mechanisms within VCNs are standardized through two primary technologies: Dedicated Short-Range Communication (DSRC) and Wireless Access in Vehicular Environments (WAVE). The U.S. Federal Communications Commission (FCC) has reserved 75 MHz of spectrum in the 5.9 GHz band specifically for DSRC, which operates under the IEEE 802.11p protocol standard [10]. Additionally, IEEE has introduced a comprehensive six-layer protocol stack in the 1906.1 draft, referred to as WAVE, which defines the communication architecture and functionalities necessary for robust VCN operations [10]. Recent studies have made significant strides in addressing the challenges of stochastic routing in dynamic transportation networks, which are particularly relevant to Vehicular Ad Hoc Networks (VANETs). One such study proposes a pre-routing framework that simulates traffic demand variations over discrete time slots, maintaining temporary network equilibrium [11]. Through offline learning across 24,000 demand scenarios, it estimates expected path times and reliability, ultimately selecting a small set of Pareto-optimal paths from thousands of candidates. This multi-objective approach balances efficiency and robustness and is scalable to large networks, making it well-suited for VANET environments. Complementing this, another study introduces a data-driven routing framework that integrates traffic sensor data augmentation and deep learning techniques to improve route reliability and traffic state observability. It includes components such as stochastic traffic assignment, multi-objective route generation, optimal sensor placement, and a Stacked Sparse Auto-Encoder (SAE) for inferring unobserved link flows [12]. This method addresses the gap between limited sensor infrastructure and full network awareness, offering a cost-effective and scalable solution for real-time vehicle routing. Together, these works lay a strong foundation for next-generation VANET routing protocols that leverage probabilistic modeling, optimization, and machine learning to improve performance under uncertainty. Despite the promising capabilities of VCNs, the WAVE standard still faces several critical research challenges.