The innovative solution? A day-time use mobile bathroom. With an attendant!
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.