I'm in the middle of the city, but mailbox is right off the highway. Cars run into it, bats have dented it, has been ran into the ditch, dug up, and defaced.
Probably just a "fun" target for bored kids who walk along the highway at night or people thinking they can turn around into the mail box.
Hasn't been that bad in the past few years though... We have the largest sized mail box that is Ok'ed by the PO and it now sits 4 feet further from the road than before on a 8x8 wood pole that has reflectors wrapped all over it.
If it's kids with bats, and you don't mind a smaller mail box, you can fill a large box with some concrete, and press a smaller mail box inside so you get basically a two layer concrete wall mail box for them to try and hit.
Also for the pole, if cars are hitting it, put some metal studs so to say around the base at various levels so if anyone does swipe it, you'll leave some nice big long nail scrapes/holes in their bumper. Mail box might be more prone to getting torn out of the ground, but makes people think twice before deciding to ram the box off the side of the road if it's gong to take their bumper with it. Can also put the pole into a large planter and fill the planter with rocks/concrete to stop cars from using your box as pole pinball.
Good luck with the mail box.