Can I get a disability placard at AAA (have MD signed form) or do I need to go to DMV?

You can bring it to AAA and get a placard guess there some AAA who can't give placard but at Pasadena, Grand at Monrovia, Chino

The lady I help needed one and we brought her signed consent from the doctor in, however they told us it needed to be mailed to Sacramentit took about 4 wks

Yes, suggest calling AAA location first to make sure they have on hand due limited number at a time.