NH has turned down plenty of federal funding. The rejection of Real ID and the fact that we still don't have a seat belt law are two examples.
I don't think it turned down highway funding.
With all due respect,
I wasn't involved in the Real ID activism although I'm aware that NH did in fact turn down federal funding. NH was selected to be a pilot state where the REAL ID would be tested. It was offered lots of federal funding to enter this pilot program. However, instead, NH passed a law to not only reject REAL ID but all similar future federal programs.
There was an effort to create a primary seat belt law in 2009. The federal government offered lots of money to NH to create such a law. I remember it all very clearly as I helped lead the effort to prevent the horrible anti-liberties law. If the issue comes up again the feds will likely offer millions of additional dollars in support of such a law. However, do not worry, I'm sure many people will do liberty activism related to such a bill. Last time, there were literally 1000s of activists organized to prevent the bill from becoming law.