> Getting hit by a 4000lb car or an 8000lb truck matters much less

It's not the weight of the vehicle but that the front of a US truck is a big flat brick wall, whereas vehicles more common in Europe have a lower-shaped hood you fall on which is engineered to dent (some even having an actuator to pop up and increase the distance to the engine) and save the life of the pedestrian (as tested by Euro NCAP)