In highway design, what is meant by "roadway cross-section"?

A "roadway cross-section" refers to a cut-through view of the roadway that details its components at a specific point along its length. This includes the various lane widths, shoulders, and drainage features, providing essential information for understanding how the roadway is structured and how it will function in terms of both traffic flow and water management.

This view is critical for engineers and designers as it affects roadway safety, performance, and the overall effectiveness of the transportation system. The proper design of lane widths ensures adequate space for vehicles to pass safely, while the incorporation of shoulders contributes to emergency situations where drivers need to pull over. Additionally, the drainage features are vital for preventing water accumulation on the roadway, which can lead to hazards like hydroplaning.

The other options do not encapsulate the complete and detailed nature of a roadway cross-section. For example, a diagram showing only the traffic lanes lacks important features like shoulders and drainage; a vertical profile only provides elevation details rather than physical features; and a chart depicting traffic speeds relates to operational characteristics rather than the physical structural details of the roadway.