ABSTRACT
There has been a steady increase in both rural and urban freeway traffic in recent years resulting in congestion in many freeway systems. The freeway traffic congestion can no longer be dealt with simply by extending more highways for economical and
environmental reasons (Kemer 1999). As a consequence, optimum use of the existing
traffic network to manage the traffic congestion has increasingly become a more
desirable alternative. Different types of freeway sections display various traffic flow
characteristics. A number of researchers have investigated the characteristics of traffic flow in freeways (Disbro and Frame 1989; Dendrinos 1994; Smith and Demetsky 1997;
Williams et al. 1998; Kemer 1999; Lee and Fambro 1999). Intelligent Transportation Systems (ITS) play a significant role in optimizing the
existing traffic network. The traffic information collected in ITS is broadcast through
variable information display boards, or radio and GPS systems. Accurate and timely
forecasting of traffic flow is of paramount importance in ITS in order to manage the traffic congestion in the freeway network effectively. A detailed understanding of the properties of traffic flow is essential for building a reliable forecasting model.
