DOCTraMS: A Decentralized and Offline Community-Based Traffic Monitoring System

The constant increase in the number of accidents and traffic jams negatively impacts several areas, including the economy, environment, and health. Since most monitoring systems require high installation and maintenance costs, especially because they depend on a central element, systems based on decentralized infrastructure have emerged as an attractive option. However, these systems cannot guarantee the synchronization between the devices' clocks since there is no centralized element. This paper presents DOCTraMS, a system that monitors and disseminates traffic conditions using a decentralized infrastructure. On-board units and roadside units do not need to be interconnected or connected to a central computer. These elements exchange information to update their tables that describe the traffic conditions of each road segment. To validate DOCTraMS, we have implemented a real IEEE 802.11 b/g prototype at Universidade Federal do Rio de Janeiro Campus. Moreover, we have simulated larger scenarios using NS-3 with traffic data from São Paulo, Brazil. When compared with a GPS, our system accuracy is higher than 90% in all scenarios.