I. Introduction
The vehicles bring convenience to the citizen. But at the same time, their continual growth inevitably leads to environmental pollution, waste of resources and traffic congestion problems. How to effectively relieve urban traffic congestion bottleneck has become a major issue faced by most of big cities [2]. Accurate estimation of the traffic state can provide guiding advices for citizens’ travel and traffic regulation. For example, the information of short-term traffic flow prediction can be provided to drivers in real time to give them realistic estimation of travel state, expected delays and alternative routes to their destinations [3]. It is believed that providing drivers with this information can help alleviate traffic congestion and enhance the performance of the entire driver-vehicle-road networks.