A base course is a layer of material used in road construction, placed directly on the subgrade. It provides a stable foundation for the surface layer, helping to distribute loads and improve drainage. Common materials for base courses include crushed stone, gravel, or recycled asphalt. The base course is essential for the longevity and durability of a road. It helps prevent deformation and cracking by absorbing stress from traffic. Properly designed and constructed base courses contribute to the overall performance of the road, ensuring safety and comfort for drivers and vehicles.