N.H. Rev. Stat. Ann. § 230-A:17

The powers granted by this chapter may be exercised by a municipality either independently of, or concurrently with, the creation of an official map pursuant to RSA 674:9-15. The designation of a highway planning corridor by a municipal layout authority shall require the approval of the planning board or local legislative body, under RSA 674:40, III, but such corridor shall not be deemed to a "street" for purposes of title LXIV.