roadbed

/ˈroʊdˌbɛd/
noun
  1. The foundation or base layer of a road or railway track, usually made of earth, gravel, or stone, on which the surface is built.
    • The railway company reinforced the roadbed to support faster trains.
    • The workers laid gravel to create a solid roadbed before paving the highway.
    • Heavy rains caused the roadbed to shift, creating cracks in the asphalt above.
What does "roadbed" mean? | whatsthatwordmean | whatsthatwordmean