n. An informal path that pedestrians prefer to take to get from one location to another rather than using a sidewalk or other official route.
2003
In areas with no sidewalks, beaten-down paths in the grass, known as "desire lines" in planning-speak, indicate yearning, said John La Plante, the chief traffic engineer for T. Y. Lin International, an engineering firm. "When sidewalks are provided, people do walk," he said.
1987 (earliest)
Study participants also drew charts of pedestrian traffic to take note of what are delightfully termed "desire lines"—paths actually made by walkers as opposed to those created on the drawing board.
Desire lines (or "natural desire lines," as they're also called) are those well-worn ribbons of dirt that you see cutting across a patch of grass, often with nearby sidewalks — particularly those that offer a less direct route — ignored. In winter, desire lines appear spontaneously as tramped down paths in the snow. I love that these paths are never perfectly straight. Instead, like a river, they meander this way and that, as if to prove that desire itself isn't linear and (literally, in this case) straightforward.