In the DUF system, trained local staff obtain voluntary and anonymous urine specimens and interviews from a new sample of booked arrestees for approximately 14 consecutive evenings each quarter. During the third quarter of 1992, all 24 DUF sites collected data from male booked arrestees, and 21 of the sites collected data from female booked arrestees. The percentage of male adult booked arrestees who tested positive for any of the 10 drugs tested ranged from 48 percent in Omaha and San Antonio to 80 percent in Philadelphia. In the majority of sites, cocaine remained the prevalent drug. Exceptions were Indianapolis and Omaha, where marijuana use was higher than cocaine use, and Denver, Phoenix, and San Antonio, where marijuana use and cocaine use were about the same. For female arrestees, the percentage of drug positives ranged from 47 percent in Indianapolis to 83 percent in Manhattan. The percentage of juvenile male arrestees/detainees who tested positive for drugs ranged from 10 percent in St. Louis to 44 percent in Washington, D.C. For juveniles, marijuana was the prevalent drug in all sites except Cleveland and St. Louis, where cocaine use was highest. 3 tables