通勤月票對於公共運輸使用之影響──雙北1,280月票與基北北桃1,200月票之分析

Implementing ESG Frameworks

近年，政府實施了一些付費公共運輸定期票政策，例如1,280月票和1,200月票，希望能夠鼓勵民眾搭乘公共運輸。然而目前國內使用嚴謹的方法分析月票政策效果的文獻仍然不足，如果月票對增加公共運輸搭乘人次的效果不顯著，月票政策的成本和效益可能無法平衡，因此本研究透過2016年至2023年臺北捷運每日進出站人次資料，以時間斷點不連續迴歸法（regression discontinuity in time, RDiT）和差異中的差異法（difference-in-differences, DID）分析2018年4月實施的1,280月票和2023年7月實施的1,200月票對於公共運輸使用的影響。
實證結果有以下發現：一、以1,280月票而言，RDiT的估計結果發現1,280月票為臺北捷運的搭乘人次帶來約5%的成長，而DID的估計結果則顯示1,280月票政策提升臺北捷運搭乘人次約2.3%。二、DID的估計結果雖然發現1,200月票提升臺北捷運搭乘人次約3%，然而RDiT的估計反而指出1,200月票讓臺北捷運搭乘人次下降，兩者估計結果的差異可能在於實施期間適逢暑假，使得RDiT難以分離出暑假及月票的政策效果。三、比較兩次月票的成效，1,200月票對於公共運輸的使用似乎未有額外的刺激，因此政府如欲進一步提升民眾搭乘公共運輸的意願，應重新檢討目前的1,200月票政策，並評估採用其他類型政策的可行性。

The government implemented some transit passes such as 1,280 monthly pass and 1,200 monthly pass to encourage people taking public transportation in recent years. Nevertheless, there are not enough rigorous literatures researching the effect of monthly pass. If these monthly passes do not increase public transportation ridership significantly, they are not cost-effective. In this study, we collect daily data of Taipei MRT ridership from 2016 to 2023, and use regression discontinuity in time (RDiT) and difference-indifferences (DID) to analyze the impact of 1,280 monthly pass implemented in 2018 and 1,200 monthly pass implemented in 2023 on public transportation usage.
The results demonstrate the following findings: First, the results from RDiT demonstrate that 1,280 monthly pass led to a 5% growth in Taipei MRT ridership, while the results from DID indicate it contributed to a 2.3% growth in Taipei MRT ridership. Seconds, the results from DID demonstrate that 1,200 monthly pass approximately increased Taipei MRT ridership by 3%, whereas the results from RDiT point out that it decreased Taipei MRT ridership. The disparity between the result from RDiT and the results from DID may be due to the implementation period of 1,200 monthly pass coinciding with the summer vacation. The problem makes it difficult to isolate the effect of summer vacation and the policy effect of monthly pass. Last but not least, we find out that 1,200 monthly pass does not provide additional stimulation for public transportation usage by comparing the policy effect of 1,280 monthly pass and 1,200 monthly pass. If the government aims to increase public transportation ridership further, it should reconsider the existing 1,200 monthly pass and assess the feasibility of other policy options.