N.H. Rev. Stat. Ann. § 239-A:7

All property of CART is hereby declared to be public property devoted to the public purpose of developing a regional public transit system to aid a greater metropolitan area faced with the solution of transit needs and shall be exempt from all taxes and special assessments of the state or any of its subdivisions. CART shall not be required to pay taxes or assessments upon its activities or upon any of its revenues.