台中市家戶機動車輛需求模式之研究－－間斷性／連續性混合模式之應用

AN APPLICATION OF DISCRETE/CONTINUOUS MODELING FRAMEWORK ON HOUSEHOLDS' CAR/MOTORBIKE DEMAND MODELS IN TAICHUNG

本研究目的在於建立家戶汽機車持有與使用之決策模式。以往研究均僅針對家戶小汽車之持有與使用做探討，研究成果雖提供相當寶貴之見解，惟仍無法適用於台灣地區此一擁有龐大機車數量的運輸環境。有鑑於此。本研究乃發展一間斷性／連續性計量經濟模式來探討家戶汽機車持有與其使用量之關係。模式中共計包括家戶之汽機車持有水準、汽車使用量、及機車使用量等三個子模式。其中由模式系統中之變異共變異矩陣校估值結果均相當顯著之情況可證實本研究所發展同時考慮汽機車持有水準與其相對應使用量之模式系統是適當的。由彈性分析可知，家戶所得並無法以政策來加以控制。在每增加一元的固定成本和變動成本之中，整體而言變動成本對於抑制汽機車里程數之效果較大。因此，政府當局應該朝此方向研討出抑制家戶的車輛持有與使用的策略。

Over the past decades there has been extensive investigation of the decision on car ownership and use. However, the decision on car/motorbike ownership and use has not been explored adequately. Without considering joint household decision on car/motorbike ownership and use, a study can be inadequate and less realistic since there is a great amount of motorbike users in Taiwan. The developed model in this research takes both cars and motorbikes into account and is explicitly based on the framework of discrete/continuous econometrics, in which the vehicle ownership choice decision, the motorbike use, and the car use are three submodels. The estimation results indicate that the framework developed in this study is suitable and adequate for the joint household decision on car/motorbike ownership and use. The policy analysis also indicates that variable costs have more effects on reducing vehicle use. It is therefore a good direction for authorities to consider adopting such strategies to reduce vehicle use.