Definitely. But not really relevant, in light of the numbers being discussed here. A 4000 lb. passenger vehicle even traveling at 75 mph has a mere 11% to 13% the kinetic energy of a 35-ton cement truck or 40-ton tri-axle doing only 50 mph. You'd have to drive your 4000 lb. vehicle at more than 200 mph to give it the same punch as either of these heavy trucks.
So, again I ask... why are we setting speed limits to the lowest common denominator? There should be at least a two-tier system, passenger vehicles versus multi-axle commercial vehicles, if not even a third category to include single axle commercial vehicles in the middle. In my own personal ethics, I drive my pickup truck slower than my sport sedan, as I know it takes longer for it to stop, and it can not as easily maneuver around any unexpected obstacles.