Article Preview
TopIntroduction
United Nations Populations presented in its technical report that for the first time, more than half of the world’s population (around 3.5 billion people) lives in urban areas. It is expected that within 35 years, two out of three people will live in a city (UNFPA, 2011). This growth has generated an increase in the demand of transportation systems with the consequent problems of traffic congestion, fatalities, accidents and pollution. In the United States, the number of registered vehicles increased from 234.6 million in 2002 to 260.3 million in 2014 (USDOT, 2017). The Texas A&M Transportation Institute informed in its technical report of 2015 that traffic congestion costs increased from 42 billion dollars per year in 1982 to 160 billion dollars per year in 2014 (Schrank, Eisele, Lomax, & Bak, 2015). According to the World Bank, approximately 20.4 percent of the total CO2 emissions in the world is produced by vehicles (International Energy Agency, 2014). Finally, the Commission for Global Road Safety showed in a technical report that road crashes kill at least 1.3 million people each year and injure 50 million, with 90 percent of these road casualties occurring in low and middle-income countries (International Transport Forum, 2015).
To improve the safety, security and efficiency of the transportation systems and enable the development of novel vehicular applications Intelligent Transportation Systems (ITS) have been developed (USDOT, 2017). These systems are characterized for utilizing communication and information technologies in vehicles and transportation infrastructures. The vision of ITS is the usage of emerging technologies to solve issues concerning to transportation systems. One of the most important components of ITS is the vehicular ad-hoc network (VANET). A VANET is a type of wireless ad-hoc network designed to provide support to a wide variety of innovative vehicular applications with the aim of bringing modern society a series of benefits in areas such as vehicular safety, entertainment and traffic control among others. Providing vehicles with relevant information about other vehicles or environmental data may improve the safety, efficiency and effectiveness of existing transportation systems. Even though VANETs are a viable solution for ITS, other technologies must be used to complement the applications, getting better results such as Internet of things for connectivity and gathering of environmental data and Big Data to provide information processing solutions and data visualization (Contreras-Castillo, Zeadally, Guerrero-Ibañez, 2016).
Although some vehicular application requirements have already been investigated in the Mobile Ad-hoc Network (MANET) environment, there still exist important challenges to be studied for correctly exploiting vehicle and traffic information (e.g. the knowledge of the dynamics of a vehicle) to improve inter-vehicular communication. Several factors such as: 1) low latency requirements for different applications, 2) extensive growth of interactive and multimedia applications and 3) the emergence of different security and privacy concerns, 4) processing of a huge amount of operational data to improve traffic management processes such as planning, engineering and operation can influence the development and adoption of applications for vehicular networks and they must be considered for the successful development of applications.
This paper provides readers with a global vision of the traffic and transportation issues and how the use of communication and information technologies contribute to the solution of different transportation challenges and focuses on VANET applications and the related development issues. It also provides an overview of the top-level application domain, showing a classification based on the usage of applications. Also, a review that shows the importance of information in vehicular networks and an analysis of the requirements for different types of applications is presented. Finally, a review of other technologies that can contribute to improve the development of applications for vehicular communication environment is presented.