The KKK adopted a highway. The joke is on them: It's black.

The line is a compact example of Stewart’s satirical method: exposing the absurdity of racist ideology by placing it in contact with mundane civic life. “Adopted a highway” evokes a public-service program meant to signal community responsibility; attributing it to the KKK highlights the contradiction between a hate group’s aims and the language of civic virtue. The punchline—“It’s black”—turns on a double meaning: the literal color of asphalt and the racial category the KKK targets. The humor depends on deflation, suggesting that bigotry can be mocked as self-defeating and ridiculous when confronted with ordinary reality.