What characterizes a through highway?

A through highway is characterized primarily by the fact that traffic entering the highway must yield the right-of-way to vehicles already traveling on it. This design ensures a continuous flow of traffic on the main roadway, reducing potential congestion and enhancing safety for vehicles using the through highway. The yielding requirement helps to facilitate a smoother transition for vehicles entering the highway from side roads or intersections, emphasizing the highway's primary function as a major route for uninterrupted travel.

The other options do not accurately describe the key characteristics of a through highway. While pedestrian access along the sides might be present in certain areas, it is not a defining feature of through highways, which primarily focus on vehicle traffic. Similarly, the notion that the highway is primarily for commercial vehicles is inaccurate, as through highways accommodate all types of vehicles unless specifically designated otherwise. Lastly, through highways are typically managed by public authorities (like state departments of transportation) rather than private entities, underscoring their status as key routes in the public transportation network.