I have a Minnesota style mailbox post that a wing plow can get under . Problem is IL. does not use wing plows much . So they do the shoulder with regular plow . Hit that box and tore it off the board and it flew 30 feet . Extra thick metal box about 1/16 inch thick . Solved snow impact but not plow impact . Really hard to straighten the thick metal . Farm implement got it this time . Shortened pipe arm 1 foot to move box back . Will see what that does . Have pull post to move it back more if needed . 25 years here and never hit by plow of farm implement before . That box was pricey .