The illusory end of stop and frisk in Chicago?

Critics of stop and frisk have heralded its recent demise in several large U.S. cities. Proponents of stop and frisk respond that when the practice ends, crime increases. Both groups typically assume that the end of stop and frisk reduces the number of police-civilian interactions. We find otherwise in Chicago: The decline in pedestrian stops coincided with an increase in traffic stops. Qualitative evidence suggests that the Chicago Police deliberately switched from pedestrian to traffic stops. Quantitative data are consistent with this hypothesis: As stop and frisk ended, Chicago Police traffic stops diverged (in quantity and composition) from those of another enforcement agency in Chicago, and the new traffic stops affected the same types of Chicagoans who were previously subject to pedestrian stops.