非意欲產出對市區公車營運效率之影響--隨機邊界分析法

Abstract

過去國內外對於汽車客運業營運績效之研究很多，但大部分僅針對業者的意欲產出（如班次、車公里、座位公里等）分析，鮮少有探討非意欲產出（如噪音、廢氣、事故等）對績效之影響。由於非意欲產出通常會伴隨意欲產出而發生，業者可能無法只生產意欲產出而不帶來一些非意欲產出，故當評估其績效時，理應將非意欲產出亦納入績效評估中，方不致偏頗。

本論文利用隨機邊界分析法，探討公車營運效率是否顯著受到肇事的影響。本研究以台北市聯營公車為研究對象，採用2001至2006年之營運資料進行分析，構建隨機邊界產出模型，選用之意欲產出項為延車公里，非意欲產出項為肇事率(不區分肇事之嚴重性)及肇事加權(區分肇事之嚴重性，依死亡、重傷、輕傷及僅財務損失賦以適當權重)，投入項則包括營業車輛數、總耗油量及員工數。研究結果發現，台北市聯營公車業之技術無效率具有顯著性。納入肇事考量時（不區分或區分肇事嚴重性），公車業技術效率之排序與未納入肇事考量時之評估結果確有顯著的不同，表示公車業者亦可藉由降低肇事的發生以提升其技術效率。研究結果亦歸納出影響台北市聯營公車營運效率之其他因子，可供業者及政府部門參考。

The issue of efficiency evaluation for bus transit has been extensively studied by transport economists; however, they ignored the effects of undesirable outputs, such as accidents, on the efficiency measurement. While producing the desirable outputs -- transport services, a bus transit in practice also accompanies with some undesirable by-products, such as pollutants and accidents, which would downgrade the environments and even cause the properties or lives loss. As these undesirable by-products are never freely disposable, measuring its productive efficiency without adjustment of their negative effects would be biased. It is therefore important to incorporate both desirable and undesirable outputs into a model to assess the bus transit efficiency in an impartial manner.

This thesis attempts to investigate if the productive efficiency of a bus transit is significantly influenced by accidents involved. Both desirable output and accident rate are incorporated into a stochastic frontier analysis (SFA) model. A panel data of ten Taipei Bus Transit firms over 2001 to 2006 is drawn for the case study, wherein vehicle-kilometer is selected as the desirable output, accident rate (without distinguishing severity) and aggregated accident score (with distinguishing severity by converting fatality, major injury, minor injury, and property loss only into proper weighted score) as the undesirable output, and fleet size, fuel, and labor as the inputs. Our findings indicate that there exists significant inefficiency in the Taipei bus transit industry as a whole. The productive efficiency with adjustment of undesirable accidents (either without or with distinguishing the severity) is significantly different from that measured without adjustment of accident effects. It suggests that ameliorating the operational safety is one of the effective means to promote the efficiency of bus transit.