"Driver of the car was pushed underneath the tractor trailer in front"...why does the US not require tractor trailers to obtain bumper heights/reinforcement that could avert this? I am guessing mainly because trucking organizations lobby versus it. In Germany, all vans have this. Hook the dolly on the front https://pullingdoubletrailers83727.blogdomago.com/8614711/a-secret-weapon-for-pulling-double-trailers