You can ignore the city police. PA state law prohibits local police from enforcing speed limits on divided highways unless the local police have made an agreement with the Pennsylvania State Police. There is currently no such agreement between the Phila PD and the PSP.

I add this here since there is no Tinicum Township catagory and the area is just south of Philly. I-95 south a couple of miles past the airport approaching the Rte 420 interchange the Tinicum Township police (some local forces can run traffic on interstate highways) and State Police use a median cross-over. It is at the end of a long lefthand curve and is shielded by the medial barriers. The curve straightens out about a 1/4 mile from the cross-over and the cars are visible from there. If the cars in front of you are jumping on the brakes it's a head-up that someone is sitting there. Tinicum has been using a couple of plain Ford Tauruses, one silver and the other dark brown for a few years in this area.