On May 1, 2002, the Philadelphia Police Department launched Operation Safe Streets, stationing officers at 214 of the highest drug activity locations in the city 24 hours a day, 7 days a week. Interrupted time series (AutoRegressive Integrated Moving Average) models on weekly data isolated citywide and local program impacts on all violent crimes, murder, and reported drug crimes. Results showed no significant impacts on citywide weekly counts for drug crimes, homicides, or all violent crimes. Geographically focused analyses showed significant localized intervention impacts for both violent and drug crimes. Analyses of high-drug-activity non-intervention sites suggest: the program impacts seen were not an artifact of history or local history; significant spatial diffusion of preventive benefits for violent crime; and probably significant spatial displacement for drug crime. Stationary targeted drug-enforcement interventions like Operation Safe Streets may differentially affect the locational selection processes behind violent crime versus drug crime.