^a Social Science Research and Evaluation, Inc., 21-C Cambridge Street, Burlington, MA 01803, USA

^b Harvard Medical School, Cambridge, MA, USA

^c Center for Studies on Alcohol, Westat, Rockville, MD, USA

Purpose: Offering drinkers free safe rides (SRs) home can prevent DWI, but some suggest that it may also promote excessive drinking. Methods: Forty-two respondents to surveys completed by 472 drinkers in barrooms reported that they used a SR during the first 9 months they were offered. Results: Their usual estimated blood alcohol concentration (BAC) was significantly greater when they used a SR than on all occasions when they drank outside their homes. However, only 24% of respondents increased their usual BAC from a “low risk” category (BAC<0.10) when drinking outside the home, to a “high risk” category (BAC≥0.10) when using a SR. The majority (72%) of respondents did not change their BAC categories. One decreased his/her BAC from ≥0.10 when drinking outside the home to <0.10 when using a SR. Implications: These findings, coupled with data showing that respondents tended to use SRs infrequently (3.69 times per year), reduce concerns about the mean increase in their BACs when using SRs. Findings do not, however, resolve the issue of whether respondents whose drinking increased when they used a SR did so because a SR was available, or decided not to drive because they drank more. Recommendations for improving SR programs are discussed.