Discription of Events: This person tailgated is for a good 20 miles if we sped up they sped up and if we slowed down they did. They even slowed down to 50. When it finally went round us they played a cat and mouse game slowing down and swerving in front of us if we attempted to go round them basically stopping us use cruise control. It was the morning as we were making a cross state drive and the roads were clear except us, pretty much. The windows are completely blacked out