# Intelligent Transportation System Technologies, Challenges and Security
## 2 Intelligent Transportation Systems
### Intelligent Transportation System Architecture  
ITS architecture is the blueprint for designing, implementing, and operating a cohesive and efficient transportation system that leverages advanced technologies to enhance safety, mobility, and sustainability. The ITS architecture consists of four main layers. These layers are the perceptive, network transmission, database, and application layers. At the network layer, the communication method of the relevant system is determined. The related servers, storage architecture, and data are collected and backed up in the database layer. In the application layer, which system and which points will be managed is determined. The perceptive layer has equipment such as a camera, speed sensor, and signal lamps.  
ITS architecture is the blueprint for creating a cohesive and efficient transportation network. By integrating various advanced technologies and subsystems, ITS architecture aims to enhance safety, improve mobility, and promote sustainability in transportation systems. It provides the framework for designing, implementing, and operating a robust infrastructure that effectively manages traffic flow, optimizes resource utilization, and responds to dynamic transportation challenges. In essence, ITS architecture is instrumental in shaping the future of transportation, enabling smarter, safer, and more sustainable mobility solutions.  
In an architecture created for planning, user services that are expected to be performed by ITS applications, the assets in which these services will be located, and the data and information flow between these assets and the services should be defined. In a simpler form, it describes what it does, where it works, and what information is transferred between its components. User services refer to the activities provided by ITS and constitute services such as providing travel information, managing traffic, collecting fares electronically, tracking traffic accidents, and tracking commercial fleets. ITS physical architecture is shown in detail in Figure 8.  
Assets are users or system administrators who interact with physical places where user services are provided, such as a traffic management center and public transport. An  
Figure 8: ITS physical architecture [30].  
example of this is GPS. The important point here is its compatibility with information and communication technologies. Suppose software or hardware components in the system are changed. In that case, the system should be able to continue to function, and interfaces and functional features between components should be clearly and consistently defined in the system architecture. Many developed countries worldwide have started studies to create ITS architecture, and it is seen that the architectures created by developed countries such as the United States, European Union countries, Japan, and South Korea, especially in the 1990s, are also taken as examples by other countries. The RSU collects traffic data from a static sensing area along a road and transmits data to traffic control devices and a central traffic management center. These devices also serve as an information source for intelligent vehicles to collect future traffic information [31]. ITS examples with GPS systems are given below in Figure 9.