Roadside sign-pole assemblies: correct placement?

[txstateends]

I'm sure there's a MUTCD or some other regulation for this.  Is there a definite national standard regarding how far from the right edge of a highway that a sign-pole assembly must be placed?

I've seen various placement distances, some as far away as next to a fence row at the edge of the right-of-way (in the case of a SOUTH US 287 reassurance as you leave Bellevue, TX, and of course, now that I look it up on GSV it's not there anymore).  I've never understood why the far-from-the-road placements of signs that some spots have had.  Maybe the installers think they won't get hit if they're farther away?  Some of the side-of-the-road BGSes on the new section of I-49 in LA north of Shreveport look like they could stand to be closer to the road, but I guess they aren't as bad as some other possible examples.

Anyway, just something I thought of that might not have had a thread before....

[roadman]

MUTCD Figure 2A-2 has this information.  http://mutcd.fhwa.dot.gov/pdfs/2009r1r2/part2a.pdf