475,106 Mistakes: When Tickets are Issued Under False Pretenses

Tens of thousands of Chicagoans are routinely issued parking tickets under false pretenses each year. After reviewing nearly 3.6 million parking tickets issued between 2012 and 2018, we leveraged multiple sources of administrative data against one another to identify more than one in eight tickets (13.2%) were issued under conditions when restrictions did not apply. More specifically, we narrowed our attention to seven different types of parking violations where compliance is
circumstantial according to factors of space, time, and weather. Our investigation took advantage of the rich administrative data made available by the City of Chicago to recreate the proverbial scene of the crime. Data from the
Office of the City Clerk, for example, allowed us to cross-reference whether residential parking only tickets were issued within restricted residential zones. Ward schedules maintained by the Department of Streets and Sanitation allowed us to triangulate
whether street cleaning tickets were issued within the designated times of restriction. Registered permits maintained by the Department of Transportation allowed us to verify if special events tickets were issued nearby a special event. The list of restrictions we considered goes on, but the logic of our analysis remains the same.