Is it possible to find the actual GPS coordinates of roads, rather than the surface they're on?
In the UK, Cyclestreet does this. I just tried a route over the Forth Road Bridge, starting and ending on the shore. On the elevation profile you can clearly see that it goes up to 40m (the height of the bridge) and is not projected onto the surface, which would be sea level:

 

Cyclestreet is based in map data from OpenStreetMap, but it is not clear if they use also data from other sources. Presumably OSM has elevation data, but I could not find a way to see this in OSM directly.