Braden sent the below pictures after deciding to check things out and discovered that there are actually two bases for the shoot. The actor trailers and camera equipment is located off North 33rd street which is a short walk to the UPENN campus while the vehicles are being stored near Walt Whitman Bridge.
While checking out the area Braden reports he saw a helicopter that looked similar to Chinese helicopter with front mounted camera used at the Bethlehem shoot the previous week. Shia Labeouf was spotted near the trailers but no other cast members.
In addition, he stumbled across Bumblebee, Optimus Prime, Ironhide, a front damaged 2009 Saturn Vue Hybrid and a new gray concept car being loaded for transport to the Walt Whitman site. The Hybrid could be for a particular scene or even a damaged TF but that is just speculation. I believe the concept car is a 2009 Chevy Corvette XR1 that is the alt mode for the Transformer Stinger. I wonder what could be happening that requires so many Transformers to converge on Sam's location?
Thanks to Braden for his report and pictures.
Update: Reading through the comments it seems the prevailing wisdom is the car either is or isn't a corvette and not the ZR1. I am not sure I agree (obviousily) but I do like the idea of it being a C7. The front end doesn't match the Fireblade at all. Note that Cheverlot is providing most of the cars used in the production again so the odds are high that the car is a Chevy car of some kind and its shape is clearly a sports car. My vote remains with te ZR1.