To study alcohol use and transportation choices by university students, we interviewed a random sample of university students as they returned to their residences late at night (10 p.m. to 3 a.m.). Interviews were conducted on all nights of the week. As part of the interview, a breath alcohol measurement was obtained using a portable breath test device. Of 1,846 persons interviewed, 1,790 provided a breath measurement. Persons who identified themselves as designated drivers were somewhat less likely to have BACs above 20 mg/dL and 80 mg/dL than those who were not designated drivers, but these differences were small. About a quarter of designated drivers had BACs of 20 mg/dL or higher. For the covering abstract see ITRD E106992.