How to Determine Whether a State Statute Preempts Local Regulation In the Same Field ?

In Duff v. Township of Northampton, 110 Pa. Commw. 277, 532 A.2d 500, 505 (Pa. Cmwlth. 1987), aff'd per curiam, 520 Pa. 79, 550 A.2d 1319 (1988), the Court identified a five-pronged inquiry for determining whether a state statute preempts local regulation in the same field: (1) Does the ordinance conflict with the state law, either because of conflicting policies or operational effect, that is, does the ordinance forbid what the legislature has permitted? (2) Was the state law intended expressly or impliedly to be exclusive in the field? (3) Does the subject matter reflect a need for uniformity? (4) Is the state scheme so pervasive or comprehensive that it precludes coexistence of municipal regulation? (5) Does the ordinance stand as an obstacle to the accomplishment and execution of the full purposes and objectives of the legislature?