Introduction to the Special Issue on Real-Time Traffic State Estimation

The term traffic state estimation refers to measuring or inferring values of the key traffic state variables, such as density, flow, speed, and delay, by using a combination of observed and derived traffic-related data. Due to recent advances in vehicular networking and sensor technology and by exploiting existing and emerging computer and communications paradigms, the task of estimating traffic state parameters in real-time has become technically feasible but remains a very challenging task.