Providing congestion information for route guidance has many advantages for users because it cannot only decrease drivers' irritation but can also work to their advantage when they choose their shortest routes on a highway or freeway network. For such situations it is very important to define the concept of traffic congestion on the basis of drivers' perceptions. A previous paper proposed definitions of freeway congestion and its dissipation by using both speed and its duration time, and also proposed a judgment method for freeway's congested sections on the basis of the definitions by using fuzzy inference. This paper proposes another judgment method deduced from the definitions directly. The judgment method proposed here and the method using fuzzy inference is applied to the actual vehicle detectors' data on a freeway and an analysis of results is presented.
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