An analysis of crime definitions, policy statements, and commentaries shows how a particular behavior gradually becomes criminal behavior. In the laws, the 1920's, 1950's, 1960's, and 1980's brought about the most notable changes. The definition of the crime becomes more specific: what was first simply called driving in a state of drunkenness or driving with impaired faculties is now defined as driving with more than 80 milligrams of alcohol in the blood. Also at first, blood, urine, and breath tests were voluntary while they are mandatory today. Among the shaping forces, the medical experts have been foremost in qualifying and quantifying the drunk driving laws. This legislation is another example of how scientific insights shape criminal law. Contemporary commentaries also show how each new law created a legal precedent which extended government power and restricted individual rights. However, such intrusion was seen as justified because of the seriousness and extent of the problem.