I adopted a highway. I'm trying to teach it to pick up after itself.

The line uses deadpan personification to frame civic cleanup work as a kind of parenting: the speaker has “adopted” a stretch of highway (as in Adopt-a-Highway programs) and jokes about teaching it manners. The humor hinges on the obvious impossibility of a road “picking up after itself,” which redirects attention to the real agents—drivers and passersby—who litter and thereby force volunteers to do the cleaning. Beneath the quip is a critique of public irresponsibility and a celebration of grassroots stewardship: the speaker’s small act of care becomes a pointed reminder that shared spaces require shared accountability.