ramp being built near I-375 on Jefferson Ave is not for TF4 but for Need for Speed. This is based on signs placed in the area reporting the weekend closure for the movie.
Since Transformers 4 is filming on Michigan 52 in Fairfield Township. While its possible for a movie to film in multiple locations with their 2nd (or more) units, I get the impression that Michael Bay prefers to direct stunts himself. In addition the camera vehicles photographed the other day are also for Need for Speed. Looking at the movie's On the Set video, they are driving exactly the kind of cars you expect to find in TF4. Thanks to J1000 for the info and pic.