Heavier cars are safer for their drivers, but far deadlier for everyone else
Here's an odd idea. Imagine being able to limit the overall momentum of a vehicle based on its expected mass. That is, a governor would cause the top speed to max out sooner for heavier vehicles, so owners would have to tolerate being just a bit slower than their more nimble road-mates.Sure, people could fudge with them, just like some do with scooters, but could be tied to penalties in the event of a collision or other traffic enforcement that detects the excess speed. Defaults matter, so the net effect would still be improved safety.