A roadbed is the foundation or base layer of a road, designed to support the weight of vehicles and ensure stability. It typically consists of compacted soil, gravel, or other materials that provide a solid surface for the road above. The roadbed is crucial for maintaining the integrity of the road and preventing issues like cracking or sinking. Proper construction of a roadbed involves careful engineering to account for factors such as drainage, soil type, and traffic load. This ensures that the road can withstand weather conditions and heavy use over time, contributing to the overall safety and longevity of the roadway system, including highways and streets.