1. In highway systems generally, an inclined section of roadway over which traffic passes for the primary purpose of ascending or descending to make connections with other roadways. It can also be an interconnecting roadway to an interchange, or any connection between highway facilities of different elevations that vehicles may use to enter or leave a designated highway. 2. For divided highways specifically, a facility that provide access to the through lanes of freeways and expressways or connects two freeways. 3. In traffic assignment, a link that connects a freeway node and an arterial node. (TRB)