why not 'Droga jest przed domem'?
przed + instrumentalis means 'in front of'...
It is correct too. And I would probably say it more often than the alternative.
is it common such use of "z"?
I found several pages that report such meaning for z + genitive: from, off, out of, (made) of.....but nothing that can be related to this sentence
Hmmm... well, you have "z przodu", "z tyłu" and "z boku" - in front of, at the back of, at the side of. "z dołu" and "z góry" would be "from below" and "from above", so they match what you already know. I guess this here is not very common.
nie "Z" tylko zzzzzzzzzzz
In Russian, Jest' doroga s pieriedi doma.
Przed domem i z przodu domu to to samo znaczenie