We have lived in this house for 27 years.
The first 12 years I must have replaced our mailbox post 7 or more times. One year from December until the next November I replaced that mailbox post 3 times. I don't know what it is. It is an auto magnet. And I don't understand why. There is a telephone pole less than 30 inches from the mailbox post. If drive eastbound you can't get to the mailbox post for the telephone pole.
So 15 years ago after the 3rd time it got knocked down in less than twelve months I had my first "Tim the Tool Man, Taylor" incident. I went to a local welding shop. I gave the guy my design and he made it. He took a rectangular piece of 1/4" steel plate and welded some 5" schedule 40 pipe to it. At the other end he welded some 1/8" steel plate. He drilled 2 groups of 4 holes in the 1/8" plate and 4 3/'8" holes in the 1/4" plate. Meanwhile, I dug a hole and built a wood form and placed it in the hole. I then mixed....3 or 4 bags of concrete and filled the form. I had made a plywood pattern of the holes in the 1/4 " plate. I put 4 "J" bolts through the pattern place the j-bolts in the concrete.
The next day after painting the new steel post, I mounted it on the concrete pad and bolted it down.
I knew without a doubt the next cars that hit that rascal.....there would be more damage on the cars than the mailbox.
Prior to yesterday, 4 vehicles had hit that mailbox post. No damage to the mailbox....
Well yesterday morning, I made a run to Fedex to pickup some parts I'd ordered. As I returned home driving my company van, I turned into my driveway, the sun hit the windshield on the van. The glare momentarily blinded me and I struck the mailbox and post.
The 1/8" steel plate that my mailbox and my neighbors mailbox was mounted to.....well it penetrated the steel on the passenger side door of my company van....and bounced out and slid the entire length of the van before I got stopped.
The moral of this story......if you build a tank proof mailbox....don't test it with one of your own vehicles!