How is gradient typically expressed in highway construction?

Answer: C — In percent

Gradient in highway construction is typically expressed in percent because it allows for a clear and straightforward understanding of the slope's steepness. In this context, the gradient percentage represents the vertical rise divided by the horizontal distance (run), multiplied by 100. This method of expressing gradient is particularly useful in highway projects, as it aligns with common engineering practices and easily integrates into design specifications and guidelines. Using percent is intuitive for estimating how steep a hill or roadway will be, helping engineers and construction teams assess factors like drainage, vehicle performance, and safety. While gradients can also be expressed in degrees or as ratios, the percent method is more prevalent in civil engineering and provides a direct way to communicate slope information to various stakeholders involved in highway construction projects.