This is paragraph V of chapter 231 section 191 of the NH DOT law book.
V. No vehicle or commercial enterprise serviced by such vehicle shall be exempt from such maximum weight limits because of prior highway use or existing use of abutting land; provided, however, that any owner of land or a commercial enterprise served by such highway, who demonstrates that such limits would entail practical difficulty or unnecessary hardship, and who complies with all conditions and regulations concerning bonding and restoration, shall be granted an exemption unless the exemption would be detrimental to public safety. For the purposes of this paragraph, "unnecessary hardship'' shall include any weight restriction which results in significant interference with a commercial enterprise or land use which existed prior to the posting of the weight restriction.
the Link
http://www.gencourt.state.nh.us/rsa/...31/231-191.htm
Not looking to argue either Tis, as I hold your opinion in high regard, but I get paid a good salary to make sure things are done in compliance with local, state and federal guidelines in regard to the construction industry. This issue comes up often.