N.H. Rev. Stat. § 265-A:17
Notwithstanding any other statutory provision of law to the contrary, a law enforcement officer may, without a warrant, arrest any person involved in a traffic accident, OHRV accident, or boating accident when the officer has probable cause to believe that such person has committed an offense, an element of which is driving under the influence of intoxicating liquors or controlled drugs, prescription drugs, over-the-counter drugs, or any other chemical substances, natural or synthetic, which impair a person's ability to drive, or both. Notwithstanding any statutory provision of law to the contrary, a law enforcement officer may make such an arrest in such officer's own jurisdiction or on the property of any medical facility in another jurisdiction in this state where the person or others are taken for treatment for injuries suffered in such traffic accident.
RSA 265-A:17
2006, 260:1. 2012, 267:14, eff. Jan. 1, 2013.