What does the term crown refer to in roadway grading?

The term crown in roadway grading specifically refers to the elevation difference between the road edge and the centerline. This design feature is essential for effective drainage as it allows for water to run off from the center of the roadway towards the edges. Properly grading with a crown facilitates the prevention of water pooling on the road surface, which can lead to hazardous driving conditions as well as deterioration of the road over time. A well-constructed crown ensures that the pavement stays dry and enhances the longevity of the roadway surface while improving overall safety for vehicles.

The other concepts represent different attributes related to roadway grading but do not accurately describe the function and definition of the crown in this context. The highest point of a roadway's elevation, the lowest point, and the slope of the road surface are all important in roadway design but they do not encapsulate the specific function of the crown.