LGD keeps chasing one particular vehicle

[blessedfarmgirl]

I have a bit of a puzzle for you dog people. Moses, my Maremma/Pyr, has never been a car chaser. He ignores them unless they stop in front of the property or come down the driveway, which is good. I don't need him chasing cars. Recently though, he decided to chase a truck a couple hundred feet down the fence line, barking. We thought it was weird for him, but didn't think much more of it. That's until he chased the same truck a few days later halfway down the entire fenceline acting like he wanted to tear it apart. He did not leave the property, but it was strange behavior from him. Then he did it again today. Another car passed a few minutes later. Nothing. No reaction.
We have talked it over several times but can make no sense of it. My thought is the owner of the truck hunts or traps varmints maybe, and he smelled them? That's the best I could come up with. Anyone else have any theories? It's not really a problem yet since he doesn't leave the property, but it's still strange and I'm hoping to get some clue of what he has against this particular pickup.

 

[Ridgetop]

Is this a truck that has been traveling regularly on the road and he has just recently started barking at it? It is more likely that the truck guy did something to upset him. Maybe having him barkig at him made him stop the truck and shout at the dog? Whatever it is he doesn't like that particular vehicle. Has the driver ever stopped at the property? As long as the LGD does not leave the property I would not worry about it unless the guy comes over in that truck. As long as the driver did not d anything too him, he may calm down about it eventually.