1. The Impact of Traffic Speed by Adverse Weather
A Fuzzy Model by
Shan-Huen Huang

2. Data Collection JAVA Program Real Time Speed Traffic Flow Weather
Visibility
Pavement Condition
Link Capacity

3. Fuzzy Model Input Output Visibility Pavement Condition
Traffic Flow/Capacity
Output
Speed Impact

4. Fuzzy Sets Pavement Condition Visibility Speed Impact
Dense(DF) <40m
Thick(TF) 40~200m
Fog(FO) 200~1000m
Mist(MI) 1000~2000m
Poor(PV) 2000~4000m
Moderate(MV) 4k~10km
Flow/Capacity
1.Free Flow (FF)
2.Normal (NO)
3.Light Heavy (LH)
4.Heavy (HE)
Pavement Condition
1.Icy (IC)
2.Very Slippery (VS)
3.Slippery (SL)
4.Not Slippery (NS)
Speed Impact
1.Tremendously (TI)
2.Seriously (SE)
3.Impact (IM)
4.Somehow (SO)
5.Slight (SI)
6.No (NI)

5. Fuzzy Logic, Inference & Defuzzification
Based on the historic data and experience to define the logic rules
Use Mamdani’s Formula
Use Center of Area (COA) Method for defuzzification

6. Future Research
Design an ANN model to Decide the Membership Function which is fuzzy-neural