考慮空間公平性的道路擁擠收費再分配

A Spatial Equity Analysis for Congestion Road Tolling with Redistribution of Toll Revenue

本研究主要探討在考慮空間公平性的情況下，擁擠收費再分配後公平性的改善情形。選擇三重往臺北市中心的運輸走廊作為研究地區，並以汽車與捷運的旅次作為研究對象。依據居住的不同地點產生空間公平性差異的概念，因居住距離捷運站較遠者往往要花更多的時間成本方能到達捷運站，因此，研究將課徵得到的擁擠稅補貼給距離捷運站較遠且搭乘捷運的旅次，以降低其搭乘捷運的成本，並分析在未課徵擁擠稅、課徵擁擠稅與課徵擁擠稅再分配的三種情境中，汽車旅次、捷運旅次與基尼係數的變化情形。研究顯示，距離捷運站超過500公尺的捷運旅次在課徵擁擠稅再分配的情境中，因為獲得補貼而大幅增加捷運旅次。在基尼係數上，未課徵擁擠稅時為0.1467，課徵擁擠稅時為0.1347，而課徵擁擠稅再分配時為0.0925，顯示擁擠稅再分配的情境中最能縮小捷運旅次間的淨效益差距，改善空間不公平性的問題，但也是三種情境中總淨效益最低的，顯示公平性的問題的改善往往需要淨效益的犧牲為代價。

This study mainly explores the improvement of fairness after the redistribution of congestion toll in consideration of spatial fairness. The transportation corridor from Sanchong City to the Taipei central business district is selected as the research area, and the commuting modes by car and Mass Rapid Transit (MRT) are selected as the research object. The difference of spatial equity comes from the distance between the residences and the MRT stations. People who live farther away from the MRT stations need to spend much more time and a higher cost to reach the MRT stations. Therefore, we redistribute the congestion toll revenues to the MRT trips that are far from the MRT stations to reduce their costs of accessing MRT. In this study, we compare the changes of car trips, MRT trips and Gini coefficients in three scenarios: no congestion tax (I), congestion tolling (II) and redistribution of congestion toll revenues (III).
The results of this study show that the MRT trips that originate in the area more than 500 meters away from MRT stations in Scenario III substantially increase due to the subsidies from redistribution of congestion toll revenues. For the spatial equity, the Gini coefficient is 0.1467 when the congestion tax is not imposed, while it decreases to 0.1347 when the congestion toll is levied, and decreases to 0.0925 when the congestion toll revenues are redistributed. This shows that the redistribution of congestion toll revenues can reduce the net benefit gap among the MRT trips and improves the spatial equity. However, it yields the lowest total net benefit among the three scenarios, showing that the solution of the fairness problem often sacrifices the net benefit.