I always make sure they know I am African American up front. I try to get that out of the way so I don't have any drama. Like driving 50 miles and no one opening the door..It does happen.lol

Race is an issue for some providers but I would think the majority just care that you are a gentleman.  As the post above says, it might be worthwhile letting them know in advance just in case they are one of the ladies who prefers not to see guys of a certain race.

Be forthright about your ethnicity too avoid wasted fuel and time. It's not considered PC for a provider to promulgate her racial preferences on her ads/website or around here; but then again no-one says a business shouldn't be able to refuse service to those not wearing shoes or shirts(or any other arbitrary reason for that fact).