Circulation diagrams show how people, vehicles, and service operations move through a site. They strip away architectural detail and reduce movement to arrows, zones, and nodes so you can see whether a site's access strategy works or breaks down.

During programming, these diagrams serve a specific purpose: they translate raw data from traffic studies, pedestrian counts, and service logistics into graphic information that communicates relationships between routes. You read them to identify conflicts (a loading dock crossing a primary pedestrian path), evaluate separation (are bikes, cars, and trucks using distinct routes or sharing corridors?), and verify connectivity (can emergency vehicles reach every building without reversing through a parking lot?).

NCA RB Objective 3.3 tests your ability to evaluate and interpret diagrammatic graphics that represent site conditions and relationships. Circulation diagrams are among the most common graphic types on the ARE because they force you to synthesize multiple movement systems into a single analysis. The exam does not ask you to draw these diagrams. It asks you to read them, spot deficiencies, and judge whether the depicted relationships satisfy program requirements. That distinction matters. You are analyzing an existing representation and making evaluative judgments about its adequacy, not producing a design solution.