On Fri, 17 Feb 2017 12:56:05 -0500, wrote:

If you are having a mailbox baseball problem, get {...] concrete
[...] concrete [...] concrete [...]
My neighbor did this in MD and totaled a corvette

Best to check your local highway codes first. Here, anything within a
certain distance of the centre-line is on the public right-of-way, and I
suspect there are rules in place against dangerous structures in order to
ensure safety of the motoring public as well as public employees.
(snow-removal, etc.)

Regardless of codes, if someone ends up dead because of something stupidly
dangerous your friend constructed, your friend can be sued. Also, whoever
owns the land can be sued. (i.e. state / municipality).