DOCS4V: Design and evaluation of a distributed and offline traffic monitoring system based on collaborative data

In distributed systems, the lack of synchronism among the devices may result in invalid information and hence incorrect decisions. This paper presents DOCS4V, a distributed system for traffic monitoring that minimises the impact of lack of synchronism by assigning a lifetime to the generated information, which is managed according to the local clock of a device. On-board and Roadside Units share data in order to update their information about the traffic conditions, in addition to propagating alerts about detected obstacles. We performed simulations using IEEE 802.11p in NS-3 to validate DOCS4V. The results reveal that DOCS4V accurately estimates the traffic conditions and efficiently distributes alerts about obstacles, with low network delay, low traffic volume and a high level of successfully delivered frames.