# Enhancing Route Guidance with Integrated V2X Communication and Transportation Systems: A Review
## 5 Related Work
As a result, the study could have leveraged more details on the types of V2X protocols and communication technologies. In addition, the simulation environment is regional; therefore, simulation test parameters need to be specified clearly to avoid unrealistic assumptions. The development of effective, reliable, and real-time vehicle RGSs has a variety of challenges, such as infrastructure requirements and technological constraints. Integrating sensors and other infrastructure elements is one obstacle to developing large-scale route guidance systems. Utilizing moving vehicles as sensors can further reduce the number of necessary sensors. These moving nodes potentially interact with one another (V2V) and the road infrastructure (V2I) due to the development of ad hoc network technology, functioning as a large-scale mesh network. This results in a particular set of issues with network development, communication, and integrity. Due to the near real-time processing needed for an effective dynamic routing system, potent computing equipment is required. Using a hybrid system could be a feasible way to reduce the need for powerful processing equipment. To minimize computation overhead, this kind of system would provide data on the condition of the roads while still allowing the user to maintain some preferences, include choosing the shortest or fastest route, avoiding congestion, minimizing travel time, minimizing fuel consumption, or selecting routes that offer a more scenic or enjoyable driving experience. These systems would maintain technological feasibility while integrating the advantages of centralized and decentralized routing systems. The demand for smart cities would be equipped with trustworthy resources for data collection, transfer, processing, and administration (i.e., decision and control). Therefore, the most feasible solution to the growing issue of traffic congestion is undoubtedly the way of the future for vehicular communication technologies when integrated with a reliable route guidance system. After discussing the related work on existing research in vehicular communication systems for ITS, particularly for RGS, we summarize the key RGS communication architectures and their characteristics in the following Table 1.  
The analysis of Table 1 highlights a strong focus on dynamic route guidance systems (RGSs), reflecting the evolving need for real-time adaptability in vehicular communication. Several models demonstrate advancements in improving communication and traffic management. For instance, SOTIS (2003) [115] and Zero Public Infrastructure (2005) [116] utilize decentralized V2V communication to autonomously collect and share data among vehicles, offering cost-effective solutions for general traffic information systems (TISs). Similarly, Novel Wireless Mesh Networks (2007) [117] provide robust and low-cost centralized V2V communication, leveraging IEEE 802.11p for better scalability and reliability. More recent models, such as DACR (2024) [108], showcase superior performance by integrating drone-based FANETs with VANETs, improving packet delivery ratios (PDRs) and reducing overhead. Flow-based Capacity-aware Rerouting (FCR) (2005) [116] enhances travel times by about 43% through centralized cloud-based resource management, while the Autonomous Vehicles' Impact on Accessibility (2024) [79] demonstrates a 220% improvement in economic value and accessibility with full AV adoption. The table also identifies four key communication architectures: decentralized V2V, decentralized V2I, centralized V2V, and centralized V2I. Each structure presents unique advantages, with decentralized architectures offering flexibility and reduced dependency on infrastructure, and centralized approaches providing structured and optimized resource allocation. Despite these advancements, notable limitations and research gaps remain. Many models,