So we are rolling down the I40 coming into Kingman AZ from Cortez hauling the hospitality trailer. In the slow lane doing 70 on a marked 75 mph freeway (2 lanes). On the entrance ramp rolls an American V twin (no slam. Relax). I'm watching him to see if I need to slow to let him merge or not as he is next to us. We look out for each other right? He looks over and see's us, speeds up to merge in front of us.........................and then slows down to 55? Not suddenly but enough. I'm on the brakes hauling down about 10 tons of moving metal and wondering WTF and What's this guy doing? I didn't jam him and keep my distance and flash my light's saying c'mon dude, Speed limit please? He grabs brakes and point's at the passing lane which would've been an option except my exit was a half mile ahead and by the time I got around him pulling that trailer I'da been screwed. So we rolled at 55 on a 75mph freeway. I was just thinking this dude is a danger to himself and others the way he moves. Not an option I would've taken on my bike. The left lane was wide open. So was it me?