估計酒駕罰則加重的政策效果

Abstract

我國酒後駕車新法於2013年6月實施，本次修法加重酒駕肇事刑責與罰金，並調降酒精濃度限制標準，成為世界最嚴格的酒駕標準之一。為了估計此修法之效果，本文使用內政部警政署之「交通事故檔」作為實證資料，其記錄每筆交通事故與涉案人的詳細資訊，並透過差異中之差異法（DD, Difference-in-differences） 進行估計。由於2013年6月的修法伴隨著道路臨檢擴大實施，故估計結果將包括罰則效果（Penalty effect）與執勤效果（Enforcement effect），其中罰則效果為因酒駕標準從嚴與罰則加重所產生之嚇阻效果，執勤效果為路邊臨檢頻率增加，使酒駕者被攔檢的機率上升所產生之嚇阻效果。所以本研究藉由僅有擴大臨檢的2012年資料來推估執勤效果。實證結果顯示，酒駕修法與擴大臨檢皆使夜間之酒駕傷亡人數顯著下降，且此效果至少維持了三個月，而日間傷亡人數的變化則不顯著。此外，我們推估出2013年修法之罰則效果至少為12%。另一方面，觀察非酒駕傷亡人數在修法前後的變化，我們發現酒駕之外溢效果不存在。最後，以相同模型對酒駕平均駕駛年齡、重度飲酒程度、酒駕事故平均乘客數及每日犯罪等進行估計，發現變數在政策前後皆無顯著不同。

In Taiwan, there was a major law reform in June 2013 that introduced criminal charge and increased fine for Driving under the influence (DUI) offenders, combined with a short period of intensified sobriety checkpoints. To this end, we use Traffic Accident Data (which provide comprehensive records of all traffic accidents with any fatalities and injuries) and difference-in-difference method to estimate the effect of law change. Because enforcement is intensified immediately after the implementation of the law change, the result will includes penalty effect and enforcement effect. To deal with this issue, we estimate the effect of intensive sobriety checkpoint operation running from June to July 2012. The result shows that both law change and intensified sobriety checkpoints significantly decrease the number of nighttime DUI fatalities and injuries, and these effects lasted at least three months. In contrast to the nighttime, the number of daytime DUI fatalities and injuries are remain unchanged. Additionally, the penalty effect of the 2013 law change is greater than 12%. On the other hand, we found that the spillover effect doesn’t exit by observing the non-DUI fatalities and injuries. Last of all, we replace the dependent variable with DUI driver’s age, degrees of heavy episodic drinking, average passengers and daily crime by applying the same DD estimation. All of them are statistical insignificance.