Does Anyone Know Why These Cameras Are Along I-75?

My brother told me that there are  new cameras being installed high on poles.  They seem to be about one mile apart.  He says he has seen them from Bowling Green to Monroe, Michigan.  Here are a few pictures.

Headed north on I-75

Some kind of control box on the bottom of the pole on I-75 off Lagrange

I was taking them with my Nokia E73 (5MP main camera) so the pictures cannot be enlarged as much as I would like.