# Urban Traffic State Sensing and Analysis Based on ETC Data: A Survey
## 5 ETC-Based Urban Traffic Management: Applications and Practices
### ETC Technology Protocols and System Design  
ETC system technology protocols and system design constitute the technical foundation for urban traffic applications. The sophistication of these underlying technologies directly affects the effectiveness and stability of upper-level applications. [PERSON] conducted in-depth research on vehicle path recognition methods in intelligent transportation systems, separately investigating two different scenarios of highways and urban roads, with a primary focus on highway situations, while conducting a preliminary exploration of urban road scenarios. Against the background of achieving province-wide highway networked toll collection in Guangdong Province, addressing ETC vehicle path recognition problems on Guangdong highways, he proposed ETC vehicle path recognition methods based on ETC identification points, replacing manual identification stations with ETC identification point systems. This system's implementation improved vehicle travel speeds, reduced operational costs, and generated favorable economic and social benefits [53]. [PERSON] conducted the research and design implementation of DSRC protocols in ETC systems, developing DSRC protocol implementation and design schemes oriented toward ETC application requirements to provide reliable communication support for ETC applications. The research combined ETC systems to conduct an in-depth analysis of DSRC protocol fundamental theories and related technical standards, analyzing the structures and characteristics of each protocol stack layer, establishing ARM-Linux software and hardware development environments, and conducting design implementation work for physical layers, data link layers, application layers, and device application layers. Through testing DSRC protocol software, design objectives were achieved, correctly implementing RSU and OBU communication functions specified by DSRC protocol standards with excellent stability [54]. [PERSON] investigated the ETC lane system software design based on DSRC devices, designing system software for ETC lanes based on existing ETC non-stop toll collection system schemes in China. The research provided brief descriptions of technical backgrounds for ETC road toll collection systems, employing 5.8G frequency RFID technology, conducted a brief analysis of the information interaction processes among computers, Road-Side Units, and On-Board Units using DSRC protocol standards at highway toll stations in China, while also conducting a comparative analysis of communication interface schemes between lane computers and roadside units, as well as lane layout schemes [55]. In traffic control strategies, [PERSON] provided an overview of road traffic control strategies, noting that traffic congestion leads to the severe deterioration of network infrastructure and correspondingly reduced throughput, which can be countered through appropriate control measures and strategies. The research provided brief discussions of future requirements for this important technical field [56]. [PERSON] et al. proposed deep learning visions for heterogeneous network traffic control from deep learning perspectives,developing supervised deep neural network systems and describing how the proposed systems work and their differences from traditional neural networks. Preliminary reported results demonstrated that the proposed deep learning systems exhibited encouraging performance in signaling overhead, throughput, and delay compared to benchmark routing strategies (Open Shortest Path First (OSPF)) [57]. These fundamental technical research efforts establish solid technological foundations for widespread applications of ETC systems in urban transportation. From communication protocol standardization to system software optimization, from path recognition algorithm improvements to deep learning technology introduction, each technical component's refinement directly affects the ETC system application's effectiveness in urban traffic management.