Discription of Events: Driving on I-94 Westbound (Michigan) towards Chicago, location began at exit 108 where it is the 69 junction of North towards Lansing and South towards Fort Wayne. Incident ended at exit 33 in Saint Joseph. Green Semi going close to 80mph, with dangerous lane shifts, and reckless passing of virtually every car. My idea was to grab their plate number, then get as far away as possible, because a vehicle of that size, going that speed with that aggressive of driving, poses a credible threat to me. Im not sure what it was carrying, but it wasnt a regular "container" type semi, it was carrying wood or something flat on the back of it. Please dont let this person continue to be a danger on our roads.