The program focuses on that portion of the jail population that is detained immediately following arrest. It was initiated to complete the Law Enforcement Assistance Administration's court improvement and delay reduction efforts. The JO/PDP employed a two-phase approach. Phase I awards, ranging up to $20,000, were for problem analysis and planning; Phase II awards, ranging up to $250,000, were provided for phase I implementation. Technical assistance was also provided. Awards were limited to jurisdictions with populations over 150,000 that were experiencing severe jail overcrowding problems. A total of 41 sites received program funding. For this evaluation, nine phase II projects and eight phase I projects were selected for site visits and case studies. Although only limited impact data are available at this time, it is apparent that phase I planning efforts have resulted in improved diagnoses of system problems, increased attention to their solutions, and a more efficient implementation of phase II efforts. Among the phase II sites in which impact data have been reported, the data show a 7.5 percent decrease in pretrial avarage daily population and a 17 percent decrease in average pretrial length of detention even though bookings have increased over 18 percent during the same period. Based on the JO/PDP experiences, three recommendations for program sites are presented. First, programs should concentrate on target populations that account for substantial percentages of local jail populations; e.g., alcohol abuse programs, programs that identify and treat the chronically mentally ill offender, and family crisis intervention. Second, process changes such as increased use of citations in lieu of arrest and prebooking misdemeanor release are suggested. Third, advisory boards to implement recommended changes should be established. Footnotes, eight figures, and eight tables are included in the summary. See NCJ 76691.