The speaker walks across a slim footbridge over a waterway and addresses it directly, as if it were a person. The bridge seems to frown over the water, steady and "incorruptible," always leading somewhere else. Around it, ordinary life goes on: boys pop wheelies over its curved back, pelicans probe the water at night, and the lagoon, which the speaker notes is technically a lagoon despite what we call it, takes in the slow current.
The mood is dreamy, a little uneasy, and tender. The speaker watches the kids "living freely" and senses the hurt they will one day cause, and perhaps suffer. The bridge, lit white on one side and orange on the other, becomes a keeper of teenage secrets and a reminder that everyone has to cross over, from one stage of life to the next. The final line, about "lazy bones," leaves a hazy, almost hypnotic feeling, as though the place itself slows you down.