Which road type is designed to move large volumes of traffic efficiently between population centers?

The choice of expressway as the correct answer is based on its primary function in the transportation network. Expressways are specifically designed to facilitate the efficient movement of large volumes of traffic over long distances. They typically feature controlled access, meaning that there are fewer points of entry and exit, which allows vehicles to travel at higher speeds without frequent stops. This design reduces congestion and minimizes travel time between major population centers, making expressways essential for regional connectivity and economic activity.

In contrast, collector streets serve to gather traffic from local streets and funnel it to major roadways, but they are not primarily intended for long-distance travel. Local streets are meant for access to homes and businesses within neighborhoods and focus on lower speed limits and more frequent intersections. The term macroclimate does not pertain to roads but refers to large-scale climatic conditions, making it irrelevant in this context.