It's quite clear. Your mirrors are there so you can see the jerk big rig driver riding your butt and attempting to intimidate you with aggressive honking, while you are simply trying to navigate the road in a safe manner. There is much we don't know in this story. How long was the truck driver held up? 1 hour? In one hour at 55 you go 55 miles. In one hour at 45 you go 45 miles. 10 miles difference in the hour, so the truck driver was put back maybe 8 minutes?. I suspect the whole incident may have taken less time, so the impact to the truck drivers day may have been minimal. When I am driving to a destination with our 14k fifth wheel, 3 kids, 2 dogs and wife in the truck, I will decide what speed and lane I need to be in depending on traffic and conditions. I don't intentionally hold people back, but it sometimes can happen. I also don't let, what I call, vehicle bullying, affect me in the least.