heavy metal..

[bugjuice]

no, not the music, the roads..

why do they call them 'metal roads' when they're just gravel/bloody big rocks?

[MSTRS:Me]

So hire cars can drive them? (they aren't allowed on 'unsealed' roads)

[ZorsT]

road metal 
British
broken stone, cinders, etc., used for making roads.
Also called metal.

http://dictionary.reference.com/search?q=metal

[xwhatsit]

I asked that question in school, but bear in mind this is not a Kiwi school so maybe the etymology is wrong (still ex-British colony though lol).

He said it came from the Latin word, `Mettalum' or something like that, which means mines, quarries, or ore. So because the roads are made out of broken bits of stone, presumably out of mines or quarries, the word `metallum' works so that's where it's supposed to come from.