As PSAs go, this one is not exactly subtle:

That is, however, the point. The sign, created by the Southeastern Pennsylvania Transportation Authority, is appearing on buses, trains and trolleys in and around Philadelphia as part of an expanded "dude it's rude" transit etiquette campaign (hat tip to Transportation Nation). The blunt signs reflect what SEPTA has learned about how to effectively shame and "reform" bad behavior in the perpetually problematic realm of crowded public transportation.

Several years ago, SEPTA tried this tack instead:

"We took a really light approach towards addressing passenger etiquette with these cartoon-like characters," says Kristin Geiger, an agency spokeswoman. "We found the messaging was too soft. It wasn’t really affecting overall behavior in the way that we had hoped."

SEPTA can't directly observe every seat hog or cell phone abuser. But the agency does keep track of complaints about them (its riders aren't shy, Geiger says). And the caricatures above apparently didn't do the trick. SEPTA got better traction with a more blunt and humorous cell phone use campaign. As a result, the agency has settled on what Geiger calls a "more direct approach" to etiquette, by which she means no beating around the bush, no please or pleasantries:

The posters intentionally leave off any SEPTA branding, which makes them feel as if they're channeling fellow rider rage more than any nagging nanny state. "We really wanted the approach to [be] as if passengers were talking to each other," Geiger says. "We’re using messaging on posters to reflect what people may think in their heads but don’t necessarily say out loud."

That also means the campaign is aimed at two audiences: the dolts who would leave their litter and curse in front of little kids, and the quietly seething angelic riders uncomfortable confronting them. To the latter group, these signs say SEPTA's got it covered, which probably goes halfway toward satisfying customer complaints anyway.

The entire task of enforcing etiquette is a tough one for transit agencies anyway. We expect them to regulate the rider experience, but they ultimately wield little control over individual riders in every car. The behavioral nudge is the best they've got.

So would these signs make you take pause — or improve your morning commute? Compared to the existing repertoire of transit etiquette campaigns, SEPTA's take is that it's better to shame bad behavior than cheer on the good, and that a few bold-faced words are more powerful than fine print. These posters are also notably absent of characters, cartoons and — this strategy is oddly popular — animals.

For your comparison, some highlights from the ever-evolving transit experiment to alter bad behavior: