本研究的主要目的是評估臺中市免費公車政策對於公車搭乘人數的影響，主要 使用2004 年3 月至2009 年10 月之臺中市公車搭乘人數之月資料，針對2009 年5-10 月所實施的免費公車政策，使用單根檢定與時間數列模式，建立沒有實施免費公車 政策的公車搭乘人數預測值，並藉由比較公車搭乘人數的預測值與實施免費公車政 策期間的實際值，實證分析免費公車政策是否具有提高公車搭乘人數之總體效果。 研究結果顯示：免費公車政策的實施確實具有增加搭乘人數的效果，臺中市2009 年5-10 月所實施的免費公車政策，平均每月增加約14 萬人次的公車搭乘人數，每 月公車搭乘人數平均約提升6.9%。

Free bus policy has been implemented in Taichung city since August 2002. This research presents new evidence of the effect of free bus policy on ridership in 2009. An appropriate time-series model is developed for this evaluation, using March 2004- October 2009 monthly ridership data. Unit root test and Box-Jenkins modeling techniques are used to forecast the ridership that would have resulted if the free bus policy is not implemented. Effects of free bus policy on ridership are identified by comparing the forecasted ridership with actual ridership. Results indicate that the ridership averagely increased about 6.9 percent after free bus policy had implemented.