Be very careful about placing any obstacle within the 50' ROW, 25' each side of center of roadbed..
I 'get' your comment.... however, I was once talking to our local TVA guy (he was lamenting all the issues THEY have out here as well) He said he wished someone (ostensibly ME) would drag some trees and line the ENTIRE roadway with them so as to block ingress/egress into their property. I did that at one location.... what happened? some idiot came out, dragged the tree so now, it's totally blocking the roadway BUT, he now had a way to get back into the woods. When I noticed that, I went back, got my backhoe and simply moved it back to where it was.... essentially blocking him in. As I was driving home, I saw someone in my mirror (back in the distance) waiving me down....but I went on home.
2-3 hours later, the Sheriff showed up at my home and asked me if I knew anything about it? Yep. I explained the above to him and explained I had TVA's permission.... and he just gave me one of those "I've got your back" smiles and said have a nice day. He didn't care that the perp blocked the road with the tree but since it was now fixed, couldn't do anything about it.
After my 2-dogs were killed (at the roadside where TVA has the road block), the gate didn't exist at the time. I have a letter signed by TVA giving me permission to line the road with rocks (think of a 36" diameter boulder) So now, where all of their ingress/egress points where, instead of finding and dragging a fallen tree there, I've lined most of this with pretty large rocks.
In the beginning, I put a single boulder there. Someone rolled it out of the way. I pushed it back, added a second rock. They moved them.... I pushed them back and added 4 more.... problem solved. It dawned on me that people are inherently lazy (at least these people) and moving one rock to get to their goal (are they the ones that had at one time, the meth lab in the woods??) anyway, moving one rock is an annoyance and they'll do it. But now, having to move 4 or 7 of these rocks.... they have finally over the years, simply left and gone to other locations so over time, the problem has gone from say, "100" down to "15". It's still an annoyance, but it's not really a problem.
However, I've learned that if I don't stay dilligent about it, things will evolve and they'll work their way back (hence my dragging the tree to a location that has essentially NEVER been a trouble spot) If they're eyeballing it and one parks there.....someone will see it and they'll use it next time, then there will be three of them back to back....
Side story.... there was once a young (punk) who parked right at our mailboxes. The no parking signs are STILL standing there (they only removed them from further down road) I spoke to the lad about where he was parking and because of the hill and 90 degree turn in the road, he was setting himself up to get his truck hit (he also had two wheels ON the pavement so he wasn't 100% off the road)
He was a bit moronic about it.... just went ahead and parked there right after I talked to him about it, essentially telling me (by his actions) to f*** off....
I dropped a rock there over the next couple days.... he came back and adjusted his parking forward/back (don't recall) so.....dropped another rock.....and a third and now, with the very steep dropoff next to this area, nobody can park there.
He's not been back since and when he did (or does in future) come back he can take pride knowing those rocks are specifically about him!