Drink…then drive away: The effects of lowering the blood alcohol concentration in Utah

In March of 2017 Utah announced its intent to lower the legal blood alcohol content (BAC) for driving from 0.08 to 0.05 g/dL. However, this change did not take effect until 2019. We employ a difference‐in‐ differences strategy on Utah counties using neighboring states as controls to test whether this policy change significantly affected the number of traffic accidents or the severity of those accidents. Results show the policy appears to temporarily decrease the total number of accidents, limited primarily to property damage‐ only accidents. We believe these results may be partially explained by drivers who, after the policy is enacted, avoid reporting property damage‐only accidents if possible. Using insurance claims data, we show there is no corresponding fall in insurance claims or payouts suggesting that the fall in total accidents likely comes from under‐reporting.