It’s loitering, that is “remaining in a public place without any apparent purpose”

Generally speaking, your right to be in public spaces is protected via your right to travel… your freedom of movement from your home to whatever other private space you would have a legal place to stay.

Depending on your jurisdiction though, you can be free to loiter, or that can be a misdemeanor.

Basically, if you stay in a particular public space, with no apparent reason, it is assumed you are doing so for illicit or illegal purposes.

So… ummm… why are you doing this?

Some states allow you to pull over and nap Some do not

From your description, I can only guess that you are (1) doing drugs (2) stalking someone (3)casing a place.