The fuzzy system uses two kinds of linguistic variables
(fuzzy sets) as inputs: speed and density. Speed levels can
be classified as fast, moderate, slow and very slow. Density
levels can be classified as low, medium, high and very high.
The output fuzzy set ranges between [0,1], according to
the following classification: 0 - represents free flow; 1/3 -
represents weak flow; 2/3 - represents moderate flow; 1 -
represents harsh conditions.