I called the first trooper on scene about an hour ago with some questions.
I asked if there were cars in the left lane that prevented him from moving over. Yes. There were two cars in the left lane as witnesses.
I asked if the tractor had any flashing lights or other indication that it was a slow-moving vehicle. Yes, the tractor had a reflective triangle. But it was covered up by the sprayer it was hauling so, therefore, not visible.
I asked if the tractor made an attempt to drive on the shoulder or if it was driving down the right lane of the highway as if it belonged there. The tractor was driving in the right lane as if it belonged there. Going 25mph in a 70mph speed zone.
I asked him if that tractor was really driving down the highway illegally because I've heard/read conflicting things. He told me that any slow-moving vehicle such as a bicycle or moped (or tractor) should not be driving on a limited access highway.
Matt's phone and personal computer, among other things, are still in the car.
There were 25ft of yaw marks - where marks are left from the tires after making a sudden turn (these are not brake marks). No brakes were applied. Matt tried to avoid colliding with the tractor at the last minute. He went to the right because of the cars in the left lane. But going 70mph and coming up on something you don't realize and don't expect to be going 25mph leaves very little time to react effectively.
I still have a couple more questions I forgot to ask but right now, I have some of the answers I've been wondering about over the last week.