When we published Driven Into Debt — our series looking at how Chicago’s traffic enforcement system unfairly burdened black and poor motorists — we knew people would want to see the raw data behind our investigation.

So we published all 66 million rows of it on our site, for free, making the city’s internal ticket-tracking system easily accessible to the public for the first time. Then, in December 2018, we used this data as the backbone for our interactive database, The Ticket Trap. While we’ve found a number of stories in the data, our analysis only used a piece of what we had; we hoped people with the time and means would be able to find more for themselves.

Since then, some 1,300 people have downloaded the file. As ProPublica Illinois’ data reporter, I wanted to know who they were and what they found, so over the past month I’ve spoken with several of them.

I encountered people from a variety of professional backgrounds, including a lawyer-turned-computer-scientist and a database-administrator-turned-reporter. A handful of responses came from students.

A few of them pointed me to aspects of the data that we had not addressed in our coverage. Kevin Lobo, a management consultant, explained how he analyzed the behavior of the Chicago police officers who wrote the most tickets. Wesley Skogan, a professor emeritus at Northwestern University’s Institute for Policy Research, mused about the placement of parking meters throughout the city. Lots of people showed me their charts. The work I saw was rigorous, creative and heartening for the practice of sharing journalistic resources with the public at no cost.

Often, people who had the support of an institution got more use out of the data than those who didn’t. Sergio Servantez, Manish Suthar and Parker Joncus, all students at the Illinois Institute of Technology, worked with the data for a class organized in partnership with ProPublica Illinois. They analyzed cases where one car got ticketed multiple times on the same day, a problem we covered in our series. The group found that duplicate tickets were most often handed out for expired registrations.

Others had a prior interest in the material. Matt Chapman, who used to work in information technology before switching careers to journalism, has been chasing Chicago ticket data since he returned from a vacation four years ago and found that his car had been towed.

Long before ProPublica Illinois obtained the data that drove our story, Chapman successfully got it from the city through an open records request. He wrote code that converted addresses in the data into geographical coordinates, then wrote a short article about the city’s most-ticketed blocks on his personal website. When ProPublica Illinois’ dataset went live, he said, he used it to push his own analysis further.

“This parking ticket project has been my way to learn data science, make some change and try to figure out the landscape of Chicago,” he said.

Lauren Nolan used the data when she was director of research at the Woodstock Institute, a nonprofit policy group in Chicago. The organization had just gotten a grant from the Ford Foundation to study how fines and fees affect low-income residents when the first article by ProPublica Illinois reporter Melissa Sanchez and former data reporter Sandhya Kambhampati appeared.

Nolan worked with Sanchez to file a separate public records request to obtain her own copy of the data, which she analyzed with geographic information system (GIS) software. The Ford Foundation grant was helpful in making use of the data, Nolan said, as was the organization’s nonprofit status, which gave her access to otherwise expensive software. Her work led to a 33-page report on the city’s “regressive revenue generation strategy.”

“I was able to earmark time for this project. It wasn’t just a hobby or something I had to squeeze in after work,” she said.

Not everyone has made progress. I heard from people who downloaded the file but got sidetracked by life and work. Others told me of the difficulty they had in wrangling such a large file into a workable format, a process they found educational but that left them little time to do much else.

“I thought I’d come back to it, and here we are a year later,” said Christopher Clapp, an economics researcher at the University of Chicago who studies transit and had planned to use the data to examine market trends for parking.

ProPublica’s Data Store has a number of free databases that include information about Illinois. You can see a list of them all here. I’m optimistic that people are using them to understand how government works and where it is failing them, and that they’re sharing their findings with others.

But I’d like to collect that information myself. Are you working with one of our Illinois databases? Write me at haru.coryne@propublica.org or call me at 708-967-5724.