What role do drainage systems play in highway construction?

Answer: B — They prevent water accumulation and erosion

In the context of highway construction, drainage systems are crucial for maintaining the integrity and longevity of the roadway. They are primarily designed to prevent water accumulation, which can lead to several serious issues, including erosion of the surrounding soil and subgrade materials. Without an effective drainage system, excessive water can collect on the road surface and in the shoulder areas, leading to potential flooding, undermining the pavement structure, and eventually resulting in pavement distresses such as cracking and potholes. Additionally, a well-designed drainage system helps to direct water away from the highway, eliminating standing water that could pose safety risks for vehicles and pedestrians. By managing stormwater runoff effectively, drainage systems contribute to overall roadway safety and durability, preventing more significant infrastructure problems down the line. This highlights their vital role in ensuring that highways remain functional and safe for the traveling public.