Why not regulate safety instead of size?
[dreams about “fun” cars like my old 2200lb Miata]
Your average Tesla is about:
- 1.9x as heavy as the Miata
- 4.3x as energy efficient as the Miata
- 1.7x faster acceleration vs Miata
- 0.2x the emissions of the Miata on a typical power mix (0x on solar)
I suspect that once you have enough mass though then it is velocity that determines the impact on safety. Getting hit at 50 mph by a Ford F-150 that has a total mass (truck plus cargo) of 9000 pounds is not going to be much more harmful to a pedestrian than getting hit by a similar shaped truck at the same speed that has half that mass.
Similarly on the other end if velocity is low enough mass won't matter. Consider for example getting hit by a freight train at 1 mph. Unless the collision knocks you over and you fall under the train it probably won't be fatal (and likely won't even injure you). Even though that freight train would have 300 times the momentum and 6 times the kinetic energy of the 50 mph 9000 pound truck it would be fine.
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)
A big truck is more deadly to smaller vehicles and we shouldn't make it unsafe to drive a regular sized car instead of one of these monstrously large trucks.
You could regulate things like requiring stop gates on trucks like semi trucks have though, which would at least help.
In a collision, all else being equal, you always want to be in the bigger car. Its literally grade 10 physics.
But we can have our cake and eat it too. Safer, environmentally sound vehicles and as big as we want them.... by simply lowering and enforcing speed limits.