Encroachment on public property

[Jennifer Lee]

Hi
I'm new here, been reading a lot. First post.
Not sure where to put this one.

Yesterday I was shown a pre-listed single family by chance. It was my brokers first time too...so no info was available.

As we drove into the lot...I immediately think...WOW 2 lots, nice!.
It had a huge driveway/parking space, you can put another house on.
The lot is significantly larger than average.
We go in....typical rehab/upgrades needed.....
So...I'm interested

I go do my due diligence:
It's an old development. 50 yrs old.
Apparently, they "planned" a road that ends next to this lot and supposedly connects to the main road.
It made no sense bc looking at the county site, if this road is ever built, it will cut into 3 other property yards and driveways, and be redundant.

Now if this was a private lot and this owner as been doing this for 40 years....it would be adverse possession.

But since this is a street for a development....it's a public lot, right?

The property line ends just a way from the garage.....entrance/driveway and parking(the size of a half basketball court) is on the street easement.

So if anyone were to buy it today, the buyer won't own the entrance to the house.

Is the owner encroaching on public property? They will probably never build the road, redundant.

My question is: do I need to remedy the issue? How complicated would it be? If I were to buy this unit...

Thanks in advance