Discription of Events: Merging from I-70 I was behind the Dodge driver, there was a semi type truck in front of him and we merged onto 435 going around 40 in a 70mph speed limit. He was not getting over after we merged so I decided to since we were going so slow and then he decided he was going to, almost hit me, and then proceeded to flip me off and speed around in the other lane on the right. I then was behind him in the left most lane because I don’t trust him behind me and went to go around because he was starting to go slow, and he rolled down his window and I believe threw something at my car because I heard a noise. Then got off on an exit. He was also tailgating me on I-70 earlier. Beware of maniacs