Which of the following best describes a highway?

A highway is typically designed to facilitate the efficient movement of vehicles over longer distances and generally includes at least two lanes for traffic, which allows for the possibility of passing slower vehicles. Moreover, highways are often characterized by their ability to accommodate higher traffic volumes and speeds compared to local roads. While at-grade intersections may exist in some contexts, they are not a defining feature of all highways, as many modern highways are designed to minimize such intersections to improve safety and traffic flow.

The other characteristics provided in the other options do not accurately reflect the nature of a highway. For instance, highways often have distributed access points such as on-ramps and off-ramps, rather than containing no fixed elements. Having only one lane in each direction would not align with typical highway design, which prioritizes multiple lanes for improved traffic management. Lastly, highways generally operate at higher speeds compared to local roads, which are designed for lower-speed, residential, or urban traffic. Thus, the defining characteristics of a highway align closely with the description given in the correct choice.