-usanht: Added shields and code. Went logoless since it appears that the logos (or at least some of them) are copyright-protected by the NPS.
It being copyright protected shouldn't deter us with this any more than it does with other protected IP used on shields, for the same reason: we have a pretty solid fair use rationale here.
The logo is subject to copyright because NPS doesn't want people selling T-shirts and other memoribilia with it without giving them a cut. They're not going to be bothered by or even have much of a case against non-commercial use in an open source project
in direct reference to the road the shield identifies.
Can always click that link to contact them and ask permission if you're really concerned though.