# Internet of Vehicles for Sustainable Smart Cities: Opportunities, Issues, and Challenges
## 1 Introduction
### Motivation
In [28], a comprehensive seven-layered architecture incorporates a D2D interaction model that facilitates various functionalities, interactions, representations, and information exchanges within the IoV ecosystem. Similarly, [29] examines the domain of D2D communications, which serves as a direct communication model connecting two or more devices without the need for an intermediary application server. However, as acknowledged in [30], D2D-assisted cellular networks bring forth numerous advantages such as high spectral efficiency, improved cellular coverage, reduced power consumption, and enhanced user throughput. In [31], two application areas of V2V communications are identified. The first area focuses on improving vehicle tracking by utilizing global positioning system (GPS) information shared through V2V communication, along with a vision system for accurate positioning. The second area introduces a simulated framework that combines embedded data, vision data, and V2V simulations to prototype an anti-collision application. In [32], the software-defined Internet of Vehicles (SD-IoV), a framework that integrates software-defined networking (SDN) and the IoV, is introduced. It aims to improve resource utilization, enhance quality of service (QoS), and support multiple requests. In [33], the authors emphasize the importance of safety in V2I communications for roadway infrastructure. In [34], they propose a cyber-physical architecture called the SIoV, which builds upon existing V2I communication technologies. The study [35] investigates the use of proportional fairness as a basis for resource allocation in a multi-rate multi-lane V2I network specifically designed for drive-thru Internet applications. The studies [36; 37; 38] discuss various network technologies and their applicability in the field of vehicle communications. Experts investigate various network technologies and their role in vehicle communications across different channels. They investigate how V2V and V2I communications impact functionality and difficulties while seeking ways to enhance safety and efficiency. The transition from ITS to IoV in smart cities marks a fundamental change in urban mobility [39]. The establishment of ITS formed a basis for more efficient traffic operation and upgraded transportation infrastructure. Through IoV advancements, vehicles link with one another effortlessly for the exchange of real-time data that supports enhanced safety and more efficient traffic. This change enables cities to enhance their level of integration as vehicles communicate with both infrastructure and one another. A safer and more efficient urban transportation environment emerges from the IoV's data-driven for effective decision-making that harmonizes with the idea of a smart city [40]. The study delivers a broad exploration of how the IoV impacts smart cities. This analysis examines the IoV influences the development of smart cities by presenting its features and challenges. In smart cities and intelligent objects such as vehicles or transportation systems, IoV facilitates smart choices that boost service delivery and improve the quality of community life. It highlights various fields where IoV implementation occurs like real-time monitoring of air pollution and road infrastructure. With the help of advanced communication technologies and data-driven urban mobility has been revolutionized by IoV. It allows urban areas to establish transportation frameworks that promote safety and efficiency. Table 1 includes a review of relevant surveys and highlights the surveyed areas along with their objectives.