Abstract
There are a number of situations in which judgments of adriver's BAC is important for practical decisions that people make which influence the incidence of impaired driving. This paper (a) indentifies the various situations in which such information is needed, noting the differences in accuracy for types of information required inthe various situations, (b) identifies the types of approaches for providing impairment or BAC information to people and (c) presents data on a variety of different techniques that have been tested recently.