Recipients of state funds under the Nebraska Public Transportation Act for any city bus system operating over regularly scheduled routes in cities of the primary and metropolitan classes may provide or designate that fares charged low-income persons may be discounted up to one-half of the rates generally applicable to other persons at peak hours for each one-way trip. Such recipient of state funds under the act may designate certain peak hours during which this section shall not apply. For purposes of this section, low-income persons shall mean persons whose income is at or below one hundred fifty percent of the current amount determined and published periodically by the federal government as the national poverty income level without regard to other resources.