本研究利用92－102年交通事故調查報告表的資料，及中斷點迴歸設計（RDD）的分析方法，探討97－102年之間酒駕罰則的4次修法對抑制酒駕交通事故的成效。實證結果發現只有102年6月13日同日施行的新修訂刑法185－3及道路交通安全規則第114條，顯著降低酒駕事故的占率約2.8個百分點（是修法前酒駕事故占率均值的44.73%），主要的原因爲刑事處罰的酒測值門檻入刑法，以及行政處罰酒駕的酒測值門檻降低；而此修法對機車和小客車車主的嚇阻作用並無明顯差別。該次的修法呈現外溢效果，同時顯著降低全台每日喝酒駕車（酒測值大於零，包含未超標酒駕者）事故件數約28件，以及交通事故件數約69件。本文的研究結果將提供修訂酒駕政策的參考。

This study examines the effects of the statutory changes in drunk driving penalties on the incidence of alcohol-involved traffic accidents. During 2003-2013, several regulatory changes regarding the punishment for drunk driving were implemented, aiming to deter driving after drinking via raising the fine, extending the license suspension period and adding jail time, etc. Employing the regression discontinuity design, we empirically investigate whether the four statutory changes have effects on the deterrence of alcohol-related traffic accidents, leading to a lower ratio of drunk-driving traffic accidents to total road accidents. Our empirical results indicate that only the last statutory change of Article 185-3 of the Criminal Code, significantly reduced the ratio of drunk driving accidents. That statutory change also had spillover effects, lessening both the number of alcohol-related traffic accidents and the total number of road accidents. Two changes contributed to the drunk-driving reducing effects. One is the insertion of the BrAC/BAC legal level in the statute of the Criminal Code. The other is the lowering of the BrAC/BAC criteria for administrative penalties for drunk driving. Our empirical results provide implications for policy aiming to ban drunk driving.