台北市天然氣公車廠牌選擇之成本效益分析

Abstract

台北市政府為改善大台北地區的空氣污染問題，考慮效法歐美等先進國家，以引進天然氣公車的方式改善傳統柴油公車大量排放廢氣而造成之空氣污染問題。但對台灣而言，天然氣公車的使用仍在起步階段，政府等相關單位須審慎評估引進天然氣公車對社會各相關層面所可能造成的影響，以決定是否應引進；此外，天然氣公車的種類很多，不同廠牌的天然氣公車除耗用的成本不同外，所能減少的污染量及其它相關效益也不盡相同。為衡量引進天然氣公車所必須付出的成本及可能獲得的價值，並評估不同廠牌天然氣公車的優劣，本研究利用成本效益分析(Cost Effectiveness Analysis, CE)的概念，建構出一個適用於天然氣公車引進與否及廠牌選擇的評估模型，並以台北市現有之天然氣公車實際試行資料，包含各公車系統之駕駛性能、污染指標、相關團體之接受度以及生命週期成本，藉由多準則決策分析方法中的理想解類似度順序偏好法(Technique for Order Preference by Similarity to Ideal Solution, TOPSIS法)結合分析層級程序法(Analytic Hierarchy Process, AHP法)，對可供評選之各公車系統加以排序，合理而有效地的分析出各公車系統的優劣，以提供台北市政府相關單位作為引進天然氣公車與否及選擇適當廠牌的參考依據。

A decision-making environment is increasingly complex, accounting for why conventional evaluation models are concerned only with economic factors and neglect those factors that cannot be evaluated by money. Consequently, such models may cause an incomplete evaluation and decision makers may ultimately select an inappropriate scheme. Therefore, this investigation develops an appropriate evaluation model capable of selecting natural gas bus brands. Natural gas bus brands are selected via the model by performing cost effectiveness analysis. Each criterion is also evaluated under cost and effectiveness categories. Two methodologies of multiple attribute decision making (MADM), technique for order preference by similarity to ideal solution (TOPSIS) and analytic hierarchy process (AHP), are then used to rank all viable alternatives to bus systems from a complete perspective. Experimental results indicate that the proposed model can efficiently evaluate cost and effectiveness of all viable alternatives to bus systems are related. Results in this investigation also provide a valuable reference for Taipei city government when selecting the brands of bus systems.