I was involved in something similar a few years ago. The short story is the county wanted to "realign" a road and it involved taking a corner of the neighborhood. And oh, by the way, we're going to expand the current road from a 2 lane road into a 4 lane with boulevard with extra wide safety zones/right of way. We could not come to an agreement as they didn't want to do anything about sound mitigation. No walls, nothing. So they told us they were going to take the land under imminent domain, and they'd see us in court........ That was the end of the discussion. We were forced to get legal help. In the end, after 5 years of bickering, they paid dearly for that legal help, but the neighborhood settled for far less than what it deserved.
Point being, if a govt. entity wants your land, they're going to take it. Then you fight it out in court. That's pretty much just the way it is, like it or not....