Define cross-slope in highway design.

Answer: B — The transverse slope designed for water runoff from the pavement surface.

The concept of cross-slope in highway design refers specifically to the transverse slope that is engineered into the roadway to facilitate water drainage from the pavement surface. This slope is critical for managing surface water runoff, which helps to prevent the accumulation of water on the road and reduces the risk of hydroplaning, flooding, and other safety hazards for vehicles. A properly designed cross-slope directs water towards drainage systems, ensuring that it does not create problems such as erosion or pavement damage. The goal of incorporating an adequate cross-slope is to maintain the integrity of the pavement while enhancing the safety of the travel surface. In highway design, this is typically expressed as a percentage or ratio that reflects how much the surface inclines from one side of the road to the other. By optimizing the cross-slope, engineers can improve overall road performance and longevity while ensuring that water runoff is efficiently managed.