# An Overview of Vehicular Communications
## 5 Conclusions  
The near future is focused on the application of ITS technologies on roads all over the world. All or parts of existing infrastructures will have to be renewed to achieve this purpose. In this sense, all national governments will have to provide public/private partnerships that will allow them to find the necessary funds for the modernization of the entire road network. It is desirable that these investments will have to provide an economic return compatible with public spending. Considering that transport systems typically depend mainly on data collected from the network, the proper design and management of the communication network is an essential step to distribute the most significant number of applications. This goal will be an essential step to make these systems robust and reliable. Apparently, the timeline can be still as long as it will be necessary to develop appropriate ITS models, more realistic concerning algorithms, analytical formulations, optimization models, and probabilistic approaches. In the main areas of interest in today's vehicular industry, there is a growing trend aimed at the cooperation between vehicles and, in general, between them and all the types of equipment of the transport sector. The purpose is to improve the safety, comfort and, possibly, also the entertainment of drivers and passengers. Starting from the technologies applied to today's vehicles, which can potentially operate independently, the review carried out in this paper has analyzed the primary systems, applications, and protocols that best meet the requirements necessary for the realization of effective technological cooperation at the service of the road safety. Among the models useful for this purpose, V2V, V2I, and V2X communications play undoubtedly an essential role. New ITS technologies will need to be integrated even more effectively with existing mobile networks, or that will be developed in future years, in order to definitively implement the so-called IoT, supporting new cloud-based services and Software Defined Networks (SDN), thus generating increasingly sophisticated services. The adoption of these networks in ITS applications is necessary to find the most extensive applicability and real implementation. As a consequence, the diffusion of ITS technologies will have to be also applied on the less frequented roads (i.e., rural areas or zones with low population density) to cover the entire road network of each state. When the coverage of the network cannot be supported, it could be guaranteed by Device-to-Device (D2D) communications and future generation mobile communication systems, such as, for instance, the 5G. Furthermore, the use of social networks and the application of crowdsourcing strategies could also represent valuable support for resources management in ITS applications. Contrarily, large private companies will be able to handle large amounts of data from connected mobile devices and vehicles, aimed at undertaking new marketing and sales initiatives. In conclusion, from the analysis carried out in this paper, it is possible to present in Table 2 the purposes and the downsides that will have to be faced for widespread dissemination of vehicular communications. A fundamental feature will be the maintenance of the road surface and signs that will result in a better application of ITS systems operations. In this case, the main impediment is economic costs as only a small part of the global road infrastructure, at present, could be ready for V2X communications and significant economic resources are required for the improvement of the road network. Another goal to be achieved will be the improvement of the technological infrastructure which will involve the complete and total operation of the V2V, V2I, and V2X communications. Nevertheless, the difficulty to be faced is represented not only by the potentially tricky implementation on a large scale but also by the lack of a common standard used universally.