As superhighways did not yet exist in 1913, it is unsurprising that Webby does not describe:

A point where a thoroughfare crosses over another thoroughfare. Either thoroughfare can be a highway, a local road, a ramp (aka slip road), a railroad, or even a bicycle path, footbridge, or animal crossing. If exit ramps connect a road and another road that passes over it, the overpass is part of an an interchange or cloverleaf. From the point of view of the upper thoroughfare, the point where lower thoroughfare goes underneath is called an underpass.

"Overpass" can also mean the structure that carries the upper thoroughfare. The term is applied to the structure only when the upper thoroughfare touches the ground immediately on either side of the overpass. Longer "overpass"es are called viaducts.