The general assembly finds that fully shielded lighting units considerably reduce light pollution. The general assembly further finds that the replacement of unshielded lighting units with fully shielded lighting units can result in substantial lowering in the wattage of the lamp needed to maintain an equivalent level of lighting on the ground, thereby realizing a considerable energy savings to the state. Therefore, it is in the public interest to require the use of fully shielded lighting units to the maximum extent possible.