"Alcohol imposes significant social costs on the residents of Montana. The state has one of the highest alcohol-related traffic fatality rates in the nation, and alcohol accounts for more than one-eighth of deaths among working aged adults statewide. 24/7 Sobriety requires alcohol-involved offenders to abstain from alcohol and submit to frequent alcohol testing; those failing or missing a test face an immediate, but brief, jail term" (p. 1). This paper evaluates the effectiveness of the 24/7 Sobriety program. 24/7 uses a preliminary breath test (PBT) twice per day immediately on release into the community. Participation in the 24/7 Sobriety program reduced the possibility of DUI re-arrest by approximately 58%.