Check your local laws, they're the first to worry about. Federal states that you only have to have 1, but local traffic laws are "in addition" to federal preparations.
This also means that just because the local doesn't say you can't do it, doesn't mean federal won't slap you for it.
Typically, only one exterior mirror is necessary, but they may also pull the "OEM equipment" BS on you, which states that if it was there from the OEM (and a single mirror wasn't available) that it still needs to be there.
__________________
"¿ʞɐǝɹɟ ɐ ǝɹ,noʎ uǝɥʍ 'ʇı ʇ,usı 'ʎlǝuol s,ʇı"
|