I suspect that total energy increases proportionally to mass, all other things (like velocity) equal, meaning an N*2 kg vehicle traveling at 100 kph has twice a

I suspect that total energy increases proportionally to mass, all other things (like velocity) equal, meaning an N*2 kg vehicle traveling at 100 kph has twice as much energy as an N kg vehicle traveling at 100 kph and since that energy factors strongly into the outcome for the other vehicle, I suspect that this means weight is what determines the impact on safety just as much, if not moreso (particularly since speeds are regulated already)