How would I join an imported road from OSM to the terrain? I am new to Blender (and very impressed).

I have imported a terrain, 3D buildings and roads into Blender using the OpenStreetMap add-on. 


The roads are elevated well over the terrain and offset in position.
If z is the altitude, I would like to zero z so that the roads rest on the terrain.
The roads are off in x and y as well. The roads run off the terrain and pass over and directly through buildings.
The default Blender mesh would essentially be underground.






Ideally, I would like to be able to apply actual distances to the Blender model in imperial or SI units and if possible include a light grid throughout a volumetric model. 

A possible workflow might be:


Use OpenStreetMap add-on to import an approximate rendering of the location of interest.
Correct placement of roads and buildings.
Apply a scale to the scene in units of miles, kilometers, etc.


I am currently researching 2 and 3.

Blend file:
Overview:




Change Clipping to some really high value to see whole thing at once.
Go to Object Mode.
With still selected roads, go to Modifier tab and remove Boolean.
Change Shrinkwrap to Nearest Surface Point and mark Keep Above Surface.