Whenever an undeveloped or unused public park area owned by the Commonwealth or any of its political subdivisions exists adjacent to any public school, the school board is authorized and encouraged to develop or improve such area in extension of such school’s programs or facilities, subject to the approval and cooperation of the Commonwealth or political subdivision, as the case may be. In the case of an undeveloped or unused public park area owned by a park authority created by more than one political subdivision, a school board in any such political subdivision is authorized and encouraged to develop or improve such area in extension of its school program or facilities, subject to approval and cooperation of the park authority.