This would be worth supporting if there weren't so many errors in it, and if the source material was more balanced (as is requested by LEO):
it isn't [N.Z.]
it may be a technical term also used by engineers, but it is also a normal, everyday word, so it doesn't need [Bauw.]
no source material for the German side
AHD supports AskOxford for the definition:http://www.bartleby.com/61/48/M0244800.html
5. Broken stones used for road surfaces or railroad beds.
The definition "metal road"= unbefestigte Straße might well be valid somewhere, but my researches showed that "metallED road" is the preferred term in BE, perhaps also in AE:http://www.wordwebonline.com/en/METALLEDROAD
A road with a hard smooth surface of bitumen or tar
- paved road, sealed road [Austral, NZ], surfaced road
Funnily enough, "metal road" IS an [N.Z.] term:http://www.chemistry.co.nz/kiwi.htm#main
metal road: a country road (usually) with a gravel or shingle surface (see also loose metal)
I'd be interested to see what the German technical term for this is - Bruchstein sounds too vague for my tastes, but I am ready to stand corrected.
dwds.de has: der aus einem Steinbruch gewonnener Naturstein; for Bruchstein, which would coincide with how I'd use the term (http://www.dwds.de/?woerterbuch=1&sh=1&qu=bru...
not supported on the basis of the provided information