計程車最適費率與空車率之研究

本研究考量市場需求面與供給面特性，建立計程車市場之需求模式與成本模式，在損益兩平社會福利最大的目標下，求解計程車最適之費率與空車率。空車率為計程車的服務品質特性之一，會影響消費者的需求，對計程車業者的成本以及費率之核算均有顯著影響。研究結果發現，在Cobb-Douglas需求函數型態下，最適空車率僅和價格彈性、等車時間彈性以及空車里程對等車時間的敏感度有關，而和需求函數之常數項及單位營運成本無關；且價格彈性對最適空車率的影響較大。最適費率亦和價格彈性、等車時間彈性以及空車里程對等車時間的敏感度有關，且和單位營運成本有關，但和需求函數之常數項亦無關。在數值實例分析中發現，當合理的價格彈性、等車時間彈性以及空車里程對等車時間的敏感度時，最適空車率為33%；而在給定每車每日營業里程後，即可透過每日最適總營業里程來求得最適的計程車數量。若每車每日以營業8小時計算，台北地區的最適計程車數量約為52,142輛，與2001年2月登記的69,164輛相較，超額供給達1萬7千餘輛，若以每日營業9小時分析，則此超額將達2萬2千餘輛，顯示台北地區計程車數量有過多之現象。由敏感度分析可得知，價格彈性對最適社會福利的影響很顯著；而當空車率在30%~40%時，社會福利的差距不大。本研究成果可做為相關主管單位制訂計程車費率與合理數量等相關交通政策之參考。

關鍵字

計程車；費率；空車率；社會福利

並列摘要

This paper aims to develop demand and cost function in the consideration of demand and supply attributes in a taxi market. The optimal fare and unoccupancy rate are simultaneously determined for maximum social welfare objective with a break-even constraint. Unoccupancy rate is one of the service quality attributes for taxi. Which will affect the quantity of demand and has great influence on operator cost and fare. With the assumption that demand function is the form of Cobb-Douglas, it is found that the optimal unoccupancy rate is the function of price elasticity, waiting time elasticity, and the sensitivity of vacant mileage with respect to waiting time. It is also found that price elasticity is the most effective factor while the optimal fare is function of those elasticity parameters affecting unoccupancy rate plus operating cost. Results of numerical case indicate that the optimal unoccupancy rate is around 33%. In the situation that each vehicle operates 8 hours per day, the optimal number of taxi is 52,142, which is significantly lower than the registered number 69,164 in Taipei City by February 2001. Sensitivity analysis indicates that price elasticity has great influence on the optimal social welfare. As the unoccupancy rate is around 30% to 40% the difference of social welfare is comparatively small. Results of this study can be used as guidelines for formulating taxi management policy.