OSM data for Road/Lane Edges ?

OSM generally maps linear features such as roads by a single line ideally located on the centre line of the feature. OSM does not, in general, store altitude data. There is a method of mapping highways as areas but it is not yet widely used (partly because it makes mapping things more difficult, but mainly because areas are not necessary for many use-cases). Equally the width tag is not widely used with highways.

To achieve what you want you will need to:

• Define areas for highways. In practice simple rules of thumb and a standard buffering of linestrings gives perfectly reasonable results. (For instance a typical residential street will be 5-6 m across, so buffer values of 2.5 to 4 m should be sensible).
• Use an external source for elevation data. Most people use SRTM data from NASA.