臺灣地區多車輛家戶小客車、機車持有與使用實證模型之研究

THE STUDY OF MULTI-VEHICLE HOUSEHOLD MIX DEMAND MODEL ON AUTO/MOTORCYCLE OWNERSHIP AND USE IN TAIWAN AREA

本研究旨在使用間斷性／連續性混合需求模型，探討多車輛家戶小客車、機車之持有與使用等決策行為之特性，而為能反映二者決策間之關係，模型係由同一效用函數進行推導，其中小客車持有數量、機車持有數量之選擇為巢式羅機模型，而使用量則為聯立之多元迴歸模型。實證校估結果顯示，小客車持有數量與機車持有數量之雙向影響關係並不顯著；持有數量與使用量間則有所影響，且相關程度係隨持有數量之增加而降低。至於多車輛家戶個別車輛使用需求間之關係方面，個別小客車之使用量呈互補關係，個別機車之使用量亦呈互補關係；而小客車使用與機車使用則呈替代關係。由模型之政策模擬分析，可顯示價格策略對小客車或機車持有之抑制效果均不大，而對抑制小客車、機車之使用需求則較具有效果。

This study tries to develop a mixed discrete/continuous demand model toanalyze the characteristics of household’s decision behavior on the ownershipand usage of automobiles and motorcycles. The ownership of auto and/ormotorcycle are modeled as nested logit models while the amount of use aremodeled as simultaneous regression models. Both models are derived from thesame utility function to avoid possible biased estimation results. Empiricalanalysis indicated that the relation between the ownership of automobiles andmotorcycles are not significant, but do exist between the mount of their use. Andthe degree of relationship in usage would decrease as more autos and/ormotorcycles are available. For multi-car families, the relation among the use ofindividual auto are compliment, same findings for motorcycle. But the relationamong the use of autos and motorcycles are substitute to each other. Simulationanalysis indicated that the cost effect on the ownership of auto or motorcycle isnot significant, but is quite significant on the use of them.