The wet-seat surprise is a common fear among Chicago transit riders. For decades the seats on CTA trains and buses have been covered with dark cloth fabric panels that, while adding nominal comfort, have the unfortunate ability to mask the presence of spilled coffee, not to mention urine or other bodily fluids. Seasoned passengers know well to perform a “seat check,” gingerly touching the fabric to test for moisture, before resting their backsides.

Soap maker Danielle Martin says that on one occasion she and other Red Line riders had to stop fellow customers from using a seat someone had vomited on. The contamination was easy to miss against the midnight-blue cloth. “And that’s why I ride my bike now,” she says.

In light of all of the cautionary tales about fetid fabric, one might ask why the CTA would even consider sticking with cloth. Chase notes that it’s not just any old material, but a tough Kevlar textile that’s difficult to vandalize. The fabric seat panels on newer cars also resist stains and some microbes. Moreover, Chase says, some riders may prefer cloth because it helps prevent rear-end slippage.