I may not be understanding your question correctly, but I see no reason why a road association couldn't represent residents of that road.
I will add that in most cases, you will be dealing with a huge uphill battle. Town are not going to set a precedent of taking over private roads. Once one is set, all the residents on every other road will follow suit with similar argument. If you have an extremely unique situation and you can make a case for justification, typically along with bringing the road to standards, you "might" have a chance.
Recognize that there is typically a town meeting on such matters, and you can bet that every person that doesn't want to see anything that can potentially increase their taxes in the get approved.
Good luck.