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 1. 文藻外語技術學院企管系助理教授 (聯絡地址：807 高雄市建國三路68 巷6 號；電話：07-3426031 轉6605；E-mail：david@thikhh.com.tw)。 2. 長榮大學航運管理系助理教授 (聯絡地址：711 臺南縣歸仁鄉大潭村長榮路1 段396 號長榮大學航運管理系；電話：06-2785123 轉2255；E-mail：jin@mail.cju.edu.tw) 。 3. 成功大學都市計劃系教授 (聯絡地址：701 臺南市大學路1 號成功大學都市計劃系；電話：06-2364454，E-mail：yschiang@mail.ncku.edu.tw) 。 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 to analyze the characteristics of household’s decision behavior on the ownership and usage of automobiles and motorcycles. The ownership of auto and/or motorcycle are modeled as nested logit models while the amount of use are modeled as simultaneous regression models. Both models are derived from the same utility function to avoid possible biased estimation results. Empirical analysis indicated that the relation between the ownership of automobiles and motorcycles are not significant, but do exist between the mount of their use. And the degree of relationship in usage would decrease as more autos and/or motorcycles are available. For multi-car families, the relation among the use of individual auto are compliment, same findings for motorcycle. But the relation among the use of autos and motorcycles are substitute to each other. Simulation analysis indicated that the cost effect on the ownership of auto or motorcycle is not significant, but is quite significant on the use of them.