This chapter, discussed about the introduction to mobile ad hoc networks and vehicular ad hoc network. It also discussed about researches like decision support system, connected vehicle technology, vehicular cyber-physical systems and system considerations for accident management.
Vehicular ad hoc network (VANET)
VANET is one of mobile ad hoc networks (MANET) and ad hoc network formed by vehicles equipped wireless communication technology. In VANET, each vehicle as a communication node and may exchange the information through the communication between vehicles or among road side units (RSUs) [2]. As the vehicles rapidly increase and wireless communication technology develops, VANET related researches have been actively carried out. VANET, a special type of MANET, performs multi-hop communication among nodes without infrastructure which but it accompanied frequent topology variation and network suspension due to high mobility of vehicles. In order to solve the problems, a protocol suitable to the situation based on efficient VANET between vehicles and RSUs will be used to provide more effective accident management service [3]. Each vehicle acts as a transmitter and receiver and delivers the information to near vehicles, competent authority and data center through RSUs when an accident takes place.
Vinh Hoa LA presented a survey of VANETs attacks and solutions in carefully considering other similar works as well as updating new attacks and categorizing them into different classes [4]. And also J. Li put forward a new routing protocol called VDLA, which is aimed at finding an optimal route that can reduce transmission delay and hop count and achieve a high packet delivery rate at the same time. VDLA adopts a junction-based geographic routing approach. VDLA incorporates the traffic density information, the distance to the destination, and the network traffic load when select the next intersection [5]. Finally, Mohamed Hamdi presented the communication architecture of VANETs and outlines the privacy and security challenges that need to be overcome to make such networks safety usable in practice. It identified all existing security problems in VANETs and classifies them from a cryptographic point of view. It regrouped, studied and compared also the various cryptographic schemes that have been separately suggested for VANETs, evaluates the efficiency of proposed solutions and explores some future trends that will shape the research in cryptographic protocols for intelligent transportation systems [6].
The existing researches
Alvert et al. proposed decision support system (DSS) which detects an accident that may occur in the tunnel. This is a system which provides an operator that treats the system in real time based on a certain method through SOS such as automatic incident detection (AID), CCTV or fire detection system when an emergency takes place in the tunnel. It forecasts an urgent situation to occur in the tunnel and provides the information for a fire, number of the wounded, vehicles locked in the tunnel to advise the seriousness of the accident. In addition, when it is necessary, it also provides the information obtained from the accident such as number of lanes of the tunnel, CC cameras, length and width of the tunnel and other provability data including possibility of the injured and serious injured through the system integrating accident model, evacuation model and decision model [7].
Ni et al. proposed Cyber-Physical Solution which provides distributed processing using connected vehicle technology (CVtech) in order to mitigate the problem of safety and efficiency of the traffic system. Since the current traffic system decides next act and controls the vehicle through monitoring surroundings of the road by driver, it solely relies the path selection on the driver. Most of the accidents take place due to wrong decision of the drivers. Thus, the communication among vehicles (V–V), Roadside infrastructures (VR), and Personal communication devices (VP) will be used in order to solve such limited problem. They avoid conflicts and jam being connected to external area and environment and captures interaction of the vehicles through Traffic Cyber-Physical System via distributed processing to provide integrated viewpoint in order to warn the accident risk in advance and support the driver to run a vehicle safely. In addition, they integrate the parts information and use the network, embedded sensors, computer database and real time communication which are perfectly suitable to the traffic infrastructure including physical elements such as the status around the road. They also provide the current knowledge based on traffic cyber-physical system with integrated online system modeling and tools by integrating the basic theory of the elements and cyber and physical process [8].
Wan et al. proposed vehicular cyber-physical systems (VCPS) and mobile cloud computing (MCC), integration architecture (VCMIA) to support an intelligent traffic system and cloud service for smooth traffic by integrating interactions between VCPS and MCC. Geographic information is provided through geographic information system (GIS) and the maintenance service of the vehicle is verified by vehicle maintenance service (VMS). VCPS verifies an application for improved traffic safety and driving and provides GIS through integrated recognition mobile. It also shares the entertainment resources and safety information of the driver and passengers through VANET vehicle cluster. It also delivers the accident information to the near drivers promptly when an accident took place. Macro layer controls all types of services through the service center to provide high quality services [9].
System considerations for accident management
Active process
Active processing is necessary in order to reduce the damages from the traffic accidents in the road traffic situation. It should have features to prevent an accident actively and provide a systematic settlement when an accident takes place. Active process has a close relation between not only physical and economic damages but also lives of the driver, passengers and pedestrians. Therefore, more prompt accident settlement should be provided when an accident takes place [10].
Traffic prevention/management process
Prevention/management processing is necessary in order to induce a correct judgment of the driver and provide a prompt settlement of an accident on the road traffic situation. The currents model proposes prevention of accident but provide insufficiency in the post-accidents situation. A prompt and systematic settlement may simply prevent an accident and also reduce the secondary and tertiary damages including loss of lives. With above reasons, a more safety accident management service shall be provided in the road traffic situation.
Data authentication
The reliability of transmitted data in the multi-users environment such as VCC environment is very important. The information of the users, vehicle conditions and user’s health are sensitive data. In addition, when the data are forged or falsified, a great amount of manpower and resources shall be wasted and the life of user could be directly affected. Thus, authenticated data must be provided in order to minimize the damages and provide highly reliable data [11].