setbacks with an old proposed road thru property

We would like to place a modular home on the property that was my grandmothers. She had a home that was there since at least 1930. At some point, the town had proposed a road through the property splitting the property into two parts with one side being about one third of the property. The house was razed last year and the city is saying there has to be front yard set backs on both road sides that would only leave about thirty feet for a homes' width. I have found a county zoning ordinance that says since it would be a corner lot, since there would be roads on two sides, the set back would be about 15 ft left on the proposed road side instead of 30 ft.
My question is would the county ordinance overrule the city ordinance?
Also, it has been many decades since the road was proposed and nothing has ever been done to actually put a road there. The area has always been a part of the yard that we have mowed since 1930. The proposed road would run into the railroad tracks and then to an existing road that already has access. There is an existing railroad crossing about 500 ft north of our property already and an old actual road that was at one time a crossing that is a continuation of the road that does run in front of our property. Also the back of our property is the end of the city limits. What are the possibilities of getting the proposed road abandonded? We have been to the city council requesting that the road be abandoned and they say that they might need to put a road there someday and refuse to give any other reasons why?
We just want to put a home there that isn't limited to only being 30 ft wide. Help!!

“My question is would the county ordinance overrule the city ordinance?”

No, I think it will be the other way around. The city ordinance will have dominance.

“What are the possibilities of getting the proposed road abandonded? We have been to the city council requesting that the road be abandoned and they say that they might need to put a road there someday and refuse to give any other reasons why?”

If the city’s general plan has a long range plan for that road, they’re going to want to keep it there. I’d suggest talking with a local attorney familiar with zoning law.

30 feet wide isn’t all that bad.