I kid you not. This photo is from a government-funded 1978 University of Texas research study, Crash Tests of Rural Mailbox Installations. Click there if you'd like to see the report.
Scroll through for photos of cute mailbox installations as well as bizarre shots of different vehicles the study used to hit mailboxes. But, to make sure this isn't a complete waste of your time, you might also want to read Appendix A, U.S. Postal Service Specifications for Rural Mailbox Installations. You'll learn, for instance, that if you don't have stamps to mail something, you can leave money in the mailbox and the carrier will take care of it for you. (That was 40+ years ago, at least, in 1978.)