N.H. Rev. Stat. § 230:81
Notwithstanding RSA 230:78-80, the department of transportation shall not be held liable for damages arising from insufficiencies or hazards on public highways or highway bridges thereon, even if it has actual notice or knowledge of them, when such hazards are caused by snow, ice, or other inclement weather, and the department of transportation's failure or delay in removing or mitigating such hazards is the result of its implementation, absent gross negligence or reckless disregard of the hazard, of a winter or inclement weather maintenance policy or set of priorities adopted in good faith by the officials responsible for such policy; and all department of transportation employees and officials shall be presumed to be acting pursuant to such a policy or set of priorities, in the absence of proof to the contrary.
RSA 230:81
1992, 188:2, eff. Jan. 1, 1993.