本研究針對2010年及2013年之台灣公路運輸運具為研究對象，透過方向邊際生產力模型探討其生產力之變化，並進一步估算其陰影價格。其中考量一個投入變量(能源消耗)、一項期望產出變量(行駛里程數)以及三項非期望產出變量(二氧化碳、硫氧化物、氮氧化物)，並用以探討九種運具分類18個運具(2011及2013年)之陰影價格變化。結果顯示，由於政府已要求台塑和中國石油進行除硫措施，相較於二氧化碳以及氮氧化物，硫氧化物的排放量相當的低；其中，二氧化碳為排放最多的汙染物，但陰影價格卻為三種汙染物中最低，因此，決策者須著重於二氧化碳的減排，建立完善的大眾運具使用環境以及擬定和擴大對於電動汽機車的補助方案等等。;This paper applies directional marginal productivity model to study the shadow price of emissions for transportation modes in the year of 2011 and 2013 with the aim that the findings can be a reference for policy makers to improve the emission of pollutants. One input variable (i.e., energy consumption), one desirable output variable (i.e., vehicle kilometers traveled) and three undesirable output variables generated by road transportation modes (i.e., carbon dioxide, sulfur oxides and nitrogen oxides) were used to evaluate directional marginal productivity and directional shadow price for 18 transportation modes. The results show that the DSP of SOx is much higher than CO2 and NOx, nevertheless, the emission of CO2 is the largest among the three kinds of pollutants. To improve the air quality, the government should pay more attention to the emission of CO2 and apply the alternative solution such as promoting the public transportation modes and subsidizing to the electric vehicles to constrain the private modes.
