It is a crime to drive while intoxicated in all 50 States. While DWI is not a new problem, statistical evidence regarding population growth, alcohol consumption, and driving habits indicates that it is growing steadily in size and impact. No two State statutes are identical, and many add qualifiers to the wording. Although several have chosen .10 percent BAC as the point at which a person is legally intoxicated, others have set ranges for figures above and below .10 percent. However, 16 States have enacted laws which provide that a person driving with a specific BAC is guilty of a DWI offense. Several Supreme Court decisions have upheld the constitutionality of .10 percent illegal per se laws, which do not allow a rebuttal of guilt. Extensive research shows that the driving ability of persons with a .10 percent BAC is impaired. Scientific measures to test BAC levels have improved considerably, and breath testing equipment has become a routine police tool. The National Highway Safety Traffic Administration has outlined a six-part police enforcement model for DWI offenses: detection, apprehension, transportation, test and record, incarceration, and testifying. Most foreign countries take the DWI situation more seriously than the United States and consequently have laws with more severe penalties that lean towards the state regarding elements of provability, such as the per se laws enacted by Scandinavian countries in the 1940's. In the United States, the chances of being arrested for DWI are still very low despite the new, stricter laws. The article includes 17 footnotes.