In order to qualify for state planning funds available to regional transportation planning organizations, the regional transportation planning organizations containing any county with a population in excess of one million shall provide voting membership on its executive board to the state transportation commission, the state department of transportation, the four largest public port districts within the region as determined by gross operating revenues, any incorporated principal city of a metropolitan statistical area within the region, as designated by the United States census bureau, and any incorporated city within the region with a population in excess of eighty thousand. It shall further assure that at least fifty percent of the county and city local elected officials who serve on the executive board also serve on transit agency boards or on a regional transit authority.