Almost sideswiped someone because they were speeding

I was in the left lane and going back to the right, I was about to change when I saw someone going about 75MPH (in a 55) in the window. Luckily I got back over. This driver sped up even faster and then was passing people left and right. I think he was going close to 100 as I could no longer see him several miles ahead. Plus he was on his phone when I saw him.

The road I was on is a long, rural highway that gets a lot of accidents because people treat it like an interstate and forget there are cross streets and driveways everywhere.