One or more contiguous counties of this state, or one or more municipal corporations which are in the same county or in contiguous counties, any one of which is adjacent to another state, may enter into an agreement, to the extent and in the manner authorized by the laws of the United States, with entities or instrumentalities of government of other states or of the United States, to provide for the creation of a regional transit commission which will provide services and facilities for a service area within this state and within one or more states adjacent to this state, for the transportation of persons in a manner that will be in the best public interest in view of the geographic, economic, population, and other factors influencing the needs and development of such service area. The exercise by a regional transit commission of the powers and duties conferred upon it shall be deemed to be the exercise of essential governmental functions of the states having territory included within the territorial boundaries of the regional transit commission.