Tonight, Chicago is expected to get 4 to 5 inches of snow. It’s not the first snowfall of the season and it won’t be the last. To stay warm and safe this winter, you’ll need plenty of heat, a great jacket, delusional optimism, and…open data.

Thanks to the ClearStreets app, Chicagoans can see which streets have been plowed and when so that they can plan their travel accordingly.

Launched two years ago, the app is the ideal representation of why open data is critical to a city’s overall health and infrastructure. In 2012, the city leveraged its data to release the Plow Tracker, an innovative app that tracks Chicago’s plows in real time. Because that data was open, Open City – the civic group that leverages available data to improve transparency and understanding of Chicago and its government – was able to build upon this platform by strategically packaging the information so that users could see if a street has already been plowed or not.

On the ClearStreets map, the app uses dark lines to show road segments that plows have likely driven over. Users can hover over the map to see if a location has been plowed or they can type in an address directly. Because this map is scraping data from the Plow Tracker, ClearStreets does not display information on private plows or smaller trucks.

According to Open City, this particular tool was inspired by the TIME article about the team that fixed the healthcare.gov website, particularly this part:

“…the people running HealthCare.gov had no “dashboard,” no quick way for engineers to measure what was going on at the website, such as how many people were using it, what the response times were for various click-throughs and where traffic was getting tied up.”

The civic group recognized that, yes, real time plow tracking is great, but people also needed to see the historical data, too.

You can check out the rest of Open City’s projects, including ‘Is There Sewage in the Chicago River,’ here and the group hosts Open Gov Hack Night every Tuesday night.

(Image via ClearStreets.org).