With a "Driving While Alcohol Impaired" (DWAI) statute, law enforcement personnel could detain those drivers whose ability to operate a motor vehicle is impaired by alcohol at BAC levels below 0.10 percent. The author reviews the scientific evidence of the effect of alcohol on driving ability at low BAC levels. DWAI statutes from eight States and the District of Columbia are examined with discussion of the placement of DWAI as a lesser offense of "Driving Under the Influence" (DUI), DWAI as a separate offense applying only to drivers under 21, and DWAI as a separate offense for all drivers, as well as the lowering of the BAC level for DUI. 16 references. (Author abstract modified)