It’s no secret that the floors of the stations in the MTA New York City Subway range from mildly gross to disgusting. With 6 million daily riders in 468 stations and 24/7 service, there isn’t a lot of time to scrub them free of grime and gum. By comparison, you could probably lick the floor of the (smaller and more modern) Munich U-Bahn to no ill effect.
The more recently renovated stations do indeed have better floors that feature granite tiles, as opposed to slabs of raw, cracking concrete. Still, granite, being rather matte, attracts its fair share of grime and the cleaning schedule isn’t exactly rigorous. And it’s expensive—so expensive, in fact, the the MTA is seriously considering going back to—you guessed it, slabs of even harder-to-clean bare concrete.
Modern concrete can be done right if it’s treated and polished. The smooth surface is essential to “cleanability.”
Several systems around the world have come to terms with the fact that eliminating the cracks between sections in addition to smoothing and polishing the floors makes them much easier to clean. Boston glazes its tiled floors in the rehabbed stations, and they stay pretty clean.
The color matters, too. Darker colors hide grime, gum and dirt and give the appearance of being clean, or at least hiding what we don’t want to see anyway. The Paris Métro, in my opinion, does it absolutely correctly. The floors are almost black, but shiny and smooth. It’s not too far off from the floors of New York’s rehabbed and new subway cars, which use speckled black floors (as opposed to the old and definitively nasty brown floors). With countless shoes trodding over both every day, both are certainly pretty filthy, but you wouldn’t know, and frankly you don’t want or need to know.
The MTA, like many lumbering government organizations, often does things a certain way because it’s “always been done that way.” Maybe they worry that smoother floors would cause accidents and related lawsuits, but I didn’t see anyone go careening in the Paris Métro. Maybe the French have better balance. Or maybe there are better materials to use. Don’t worry guys, it’s OK to experiment.