Measuring safety awareness in cooperative ITS applications

Cooperative Intelligent Transportation Systems (C-ITS) are key component of the future road traffic management system. To evaluate and analyze the reliability of various applications supported by C-ITS, realistic performance metrics are required. Such metrics serve as a performance indicator and help in tuning the wireless transmission parameters to maintain required quality of service. The essential purpose of a C-ITS is to enhance the vehicle safety awareness and hence, provide an accurate information of vehicles in the vicinity through regular sharing of cooperative awareness messages (CAMs). The existing metrics such as packet delivery ratio provide quantitative measure of vehicle safety awareness but do not consider the accuracy of received information. In this paper, we propose two novel safety awareness metrics (SAM) to enhance the measure of vehicle awareness by considering factors such as age and weight of a received CAM in the perspective of C-ITS. Using simulation results in NS-3, we show that the current metrics provide an optimistic view of vehicle safety awareness and proposed metrics serve as a valuable gauge to analyze the reliability of applications in C-ITS.