“…Examples of these methods include g‐estimator (Athol, 1965; Coifman et al, 2003; Lin et al, 2004), log‐linear regression method (Wang and Nihan, 2000), exponential smoothing method (Hellinga, 2002), catastrophe theory method (Hall, 1987; Pushkar et al, 1994), sequence method (Neelisetty and Coifman, 2004), Kalman filters (Dailey, 1999; Ye et al, 2006), Bayesian approach (Li, 2009), and distribution method (Coifman and Kim, 2009). The Kalman filter methods reported good results compared with other existing methods (Ye et al, 2006), but they have an inherent assumption of Gaussian distribution on speed that may not be always valid. Studies have found that the normal distribution may describe speed distribution accurately only for homogenous traffic streams with light to moderate traffic volume.…”