Abstract
Research and/or Engineering Questions/Objective
Connectivity of different traffic participants provides a huge potential to improve traffic safety and efficiency. V2X-communication for example enables vehicles to perceive the position of a vulnerable road user (VRU) or another vehicle in spite of obstructions in the field of view. In urban environments the characteristics of the driving environment with respect to radio wave propagation vary significantly, which affects the performance of connected systems. The objective of this paper is to present an approach to reliably assess the performance of connected safety systems in different radio environments and apply this approach for a connected emergency brake system.
Methodology
In order to derive requirements for the impact assessment approach, first of all a prototype implementation of a connected safety system is designed and implemented. Characteristics of data transmission such as packet delivery rate or latency depend on the communication technology used, e.g. dedicated short range communication (IEEE 802.11p) or LTE mobile communication. The system is simulated and the impact of different communication characteristics on the safety effect is examined in a sensitivity analysis. Based on these results requirements for a real-world assessment of the connected system are derived. The relevant characteristics of communication are measured at public intersections and reproduced at the test site as well as in simulations. The system is implemented and assessed in real world driving tests in a dedicated test environment.
Results
This paper summarizes and characterizes the most important influencing factors on the performance of connected active safety systems in urban traffic environments in a sensitivity analysis. This includes for example packet delivery rate or latency which might again depend on radio characteristics of the environment. Additionally real-world measurements of a prototype system assessed on a test track are discussed and a comparison of simulations versus real-world measurements is presented.
The paper describes a holistic approach to the impact assessment of connected systems that utilizes simulations as well as real-world tests and considers the effect of different characteristics of communication. The impact of a connected safety system is derived by multiplying the exposure with collision probability.
Limitations of this study
This study links the quality of the communication interface with the effectiveness of a communicationbased safety system instead of explicitly modeling data transfer characteristics. Detailed simulation of radio wave propagation and multi ray tracing is not performed. Additionally the aspect of driver acceptance is not covered in detail.
Novel aspects in this paper
In previous publications the authors presented a methodology to estimate the impact of positioning accuracy on the effectiveness of a pedestrian safety system. This work however did not consider aspects of the communication system which is addressed by the proposed paper.
Conclusion
Communication characteristics significantly vary depending on environment characteristics and need to be considered in system design and assessment. For this reason a holistic approach that takes the relevant aspects of communication into account is necessary for a sound impact assessment.
Key Words: V2X-Communication, Connectivity, Active Safety, Impact Assessment Research