The flow of traffic, as the name suggests, refers to the predominant direction of movement in the aisles or sections of a medium-sized or large self-service store. It is crucial to consider this flow as it influences the smoothness of customer movement, particularly when it comes to shopping cart traffic. Furthermore, it plays a key role in space organization and merchandising optimization. Generally, from the checkout area, the flow of traffic in a main aisle is from right to left.

Within a section or shelf, the dominant flow of traffic can be strategically used to encourage customers to walk past high-profit products before reaching the more basic items they might be looking for. This can be illustrated with concrete examples of store redesigns that take the flow of traffic into account.