Effects of Maine's 0.05% legal blood alcohol level for drivers with DWI convictions

To determine whether a Maine law lowering the legal blood alcohol limit (BAL) from 0.10% to 0.05% for people convicted of driving while intoxicated (DWI) reduced the involvement of this group in fatal crashes.

The authors calculated changes in the proportions of fatal crashes involving drivers with prior DWI convictions from the six-year period before enactment of the law to the six-year period following enactment of the law, comparing Maine with the other New England states.

In Maine, the proportion of fetal crashes involving drivers with recorded prior DWI convictions declined 25% following passage of the 0.05% DWI law, while the proportion rose in the rest of New England during the same years. The proportion of fatal crashes involving drivers with recorded prior DWI convictions and illegal alcohol levels also declined significantly in Maine, as did the proportion of fatal crashes involving fatally injured drivers with recorded prior DWI convictions and illegal alcohol levels. Most of the latter decline was due to a decline in alcohol-related fatalities of previously convicted drivers with very high BALs, of 0.15% or higher, at the time of the fatal crash. Each of these declines in Maine was significant relative to the rest of New England.

Other states should consider instituting 0.05% BAL limits for convicted DWI offenders.