One doorbell ding came from a guy who sheepishly admitted he had just collided with our mailbox, which sits on the outside of a gentle curve and sticks out, IMO, a bit too far into the street.
This not being my first time in this rodeo, I allowed as how if he’d replace whatever broke, I’d do the fixing and it’d be all good. As it turned out, the only broken part was the foamed-plastic post, which split neatly along its length around the crosspiece hole. After looking things over, I said I’d just epoxy it together and call it done.
That afternoon, I mixed up a generous cup of the casting epoxy I’d been using for coasters and suchlike. It is now well past its best-used-by date and somewhat cloudy, but I figured it would suffice for the purpose; nobody will notice cloudy epoxy on a mailbox post.
I have Too. Many. Clamps. and know how to use them:
He departed, quite literally in tears, over my not raking him through the coals. I figured anybody who’d stop and admit to property damage needed encouragement, not chastisement, and replacing the headlight on his pickup would be more than enough punishment.
That was easy.
The Smell of Molten Projects in the Morning 
If the post box protrudes ‘too far’ into the street, can’t you relocate it to prevent future incidents? The folks across the street look to have a step function on their curb…
That would require me to perform actual work while digging it up; I shall procrastinate until the next errant driver wipes out the post.
Verily: never put off until tomorrow that which can be ignored forever.
That indent across the street is an optical illusion due to looking diagonally across the end of their driveway on the curve. The curbs form a nearly straight line (with a storm drain at the lower side) with the mailbox door just over the curb.