Main-traveled way
Main-traveled way means the traveled way of an Interstate Highway on which through traffic is carried. In the case of a divided highway, the traveled way of each of the separated roadways for traffic in opposite directions is a main-traveled way. It does not include such facilities as frontage roads, turning roadways, or parking areas.
Source
23 CFR § 750.102
Scoping language
The following terms when used in the standards in this part have the following meanings: