Create buffer-lines in QGIS alongside Vector lines

I am currently doing a map of a farm, to see which roads needs to be repaired.

Those roads are either one sided fenced, on both sides fenced or not fenced at all. I want to make buffer lines around the already mapped roads (vector lines), which have fences. Something like this:

I hope this is possible to understand. Of course I can draw additional lines alonside those paths... but this is a hellofa work.

I work with QGIS :)

Thanks for your help in advance!

Lukas

Answer

GRASS GIS offers this through v.parallel. It can be used from QGIS with the GRASS Toolbox or, even easier, with the Sextante plugin.