In PA, safety inspections include brake lining thickness (two wheels pulled if I recall correctly), head light operation, turn signals operating properly, backup lights operating properly, horn operation, tread thickness on tires, exhaust system integrity, no holes in the floor of the vehicle. There may be other things they check and perhaps another Pennsylvanian wants to chime in on that. These inspections are required once a year. Some years back, they were required TWICE a year. That was a pain!
I imagine they could fail you for having too dark a window tint or wheels that stick too far out past the fenders.