If it goes wrong will the truck driver assume any responsibility? It's all on the person that is doing the passing. I do understand what you are saying, maybe the truck driver is sitting much higher up etc, but still bad idea to me. Just like if someone flashes their lights that it's ok for me to move over after I pass them. It's still on me to be sure it's ok to move over. If I did clip them I will be at fault either way.