Is another word for the road of a bridge or highway, deck, suspension, truss, or viaduct?

The deck is the part you walk or drive upon.

Suspension refers to a type of bridge construction. The easiest example are bridges with cables.

Trusses are structural members similar to beams, but made up of many smaller pieces. Think of freeway sign structures or outdoor concert stage rigging.

A viaduct is bridge. Specifically, a bridge constructed in a similar manner to roman aqueducts will smaller spans touching the ground rather than a single span.