These centers are alternatives to incarceration for repeat drunk-driving offenders. This evaluation assessed the centers' impact on the recidivism and rearrest rates of multiple drunk driving offenders released from these facilities. The Middlesex County Jail and House of Correction in Billerica was used as a comparison (nontreatment) site to measure impacts at the two centers. Postrelease followup data were obtained at 12, 18, and 24 months. The major finding is that the Longwood Treatment Center has a statistically significant lower recidivism rate at each followup period than either WMCAC or the Middlesex County Jail and House of Correction. The research did not document a treatment effect at WMCAC, since its recidivism and rearrest rates were not significantly different than the Middlesex releasees. The report recommends further research on WMCAC, reconsideration of the target population at WMCAC, and continued emphasis on the aftercare component at Longwood and WMCAC. 6 tables, 29 references. (Author abstract modified)