Roadbed

имя существительное полотно дороги

Большой англо-русский словарь

Roadbed

дорожное полотно

Англо-русский научно-технический словарь

Roadbed

noun 1. a. the bed on which the ties, rails, and ballast of a railroad rest b. the ballast or the upper surface of the ballast on which the ties rest 2. a. the earth foundation of a road prepared for surfacing b. the part of the surface of a road traveled by vehicles

Merriam-Webster's Collegiate Dictionary