Urban Traffic Monitoring with the Help of Bus Riders

Real-time urban traffic conditions are critical to wide populations in the city and serve the needs of many transportation dependent applications. This paper presents our experience of building a participatory urban traffic monitoring system that exploits the power of bus riders' mobile phones. The system takes lightweight sensor hints and collects minimum set of cellular data from the bus riders' mobile phones. Based on such a participatory sensing framework, the system turns buses into dummy probes, monitors their travel statuses, and derives the instant traffic map of the city. Unlike previous works that rely on intrusive detection or full cooperation from "probe vehicles", our approach resorts to the crowd-participation of ordinary bus riders, who are the information source providers and major consumers of the final traffic output. The experiment results demonstrate the feasibility of such an approach achieving fine-grained traffic estimation with modest sensing and computation overhead at the crowd.