What must be true about the underlying material for optimal roadway support?

• A. It must be visually appealing
• B. It must be expensive
• C. It must be well drained and structurally sound
• D. It must be light and airy

Answer: (C)

For optimal roadway support, the underlying material must be well drained and structurally sound. This is essential because the foundation of a roadway plays a crucial role in distributing loads from traffic and preventing structural failures such as cracking or deformation. Well-drained materials help minimize water accumulation, which can weaken the support structure and lead to issues like erosion and settling. Additionally, structural soundness ensures that the materials can withstand the stresses imposed on them by vehicles, preventing long-term damage and ensuring the roadway's longevity and safety.