Ariel Schwartz of Co.Exist writes that San Francisco has a poop problem. The city suffers from an excess of excrement on public streets and even in the innards of subway escalators, where it renders them unusable. Part of the issue is that the city has never effectively dealt with its homeless population (there up to 10,000 homeless in the city), and a failure to provide public bathrooms that aren’t eventually shut down because people use them to do drugs.

Now that’s changing.

This past summer, San Francisco announced the launch of Tenderloin Pit Stop, a series of mobile bathrooms that each comes with a sink, two toilets, a dog waste station, and a needle disposal bin. An attendant stands outside of each bathroom during the day, and bathroomgoers get five minutes to do their business before the attendants come calling. Every evening, the toilets are taken away by the Department of Public Works (DPW) and cleaned.

Each bathroom is placed strategically based on the DPW’s reports of human feces on the street. Those reports tend to be clustered in the city’s Tenderloin neighborhood, as you can see on this map, called (Human) Wasteland. Created by a web developer named Jennifer Wong, the map uses complaints about feces and urine phoned into DPW in 2013 (over 5,000 in total) to figure out where the poop problem is worst.