I.When the legislative body of any municipality finds that the public health, safety, morals and general welfare so requires, it may undertake to study the question of providing public parking facilities. For the purpose of such study said legislative body may appoint or authorize its governing board to appoint an investigative and planning board or may contract with private planners or developers which investigative and planning board or private party shall study the parking needs and conditions in said municipality and shall propose a plan for providing one or more public parking facilities; and said legislative body may appropriate such sums of money as are reasonably necessary therefor.II.The plan referred to in paragraph I of this section, in addition to providing a detailed proposal for the construction of one or more public parking facilities shall show that there is a need for public parking facilities, that the facilities proposed therein are proposed with respect to that need, and shall include an estimate of construction costs and operating expenses and the method of financing and paying the same. Any such plan shall provide that construction costs or operating expenses shall be raised by assessments as provided in RSA 231:120 and the plan shall so indicate and shall determine the boundaries of any prescribed area within which special benefit assessments shall be levied, which area may but need not be coterminous with the municipality. No such plan shall be adopted unless it provides that at least 50 percent of the construction costs and operating expenses shall be raised by assessments upon the owners or lessees of leasehold interests whose lands receive special benefits therefrom and such plan shall also provide that no more than 25 percent of such construction costs and operating expenses shall be raised from general revenues and no more than 25 percent of such construction costs and operating expenses shall be raised from motor vehicle permit fees as provided in RSA 261:154.III.The legislative body of a municipality may adopt the proposed plan with or without amendment and proceed with the construction of the public parking facilities. Nothing herein shall be construed to prevent the municipality from thereafter changing or amending the plan upon a finding by the legislative body that the public interest requires such change or amendment. RSA 252-A:3. 1969, 493:1. 1981, 87:1, eff. April 20, 1981; 146:5, XIII, eff. Jan. 1, 1982; 146:7, V, eff. May 22, 1981.