In reality, any 'vehicle' which does not meet both passenger car safety and passenger car fuel economy standards [1] should only be allowed to be licensed as a "commercial" vehicle and should pay "commercial" rate (higher) taxes (and maybe even require a "commercial" stamp on one's drivers license to operate). If the states had done this when SUV's first appeared on the scene, we might not have nearly every car on the road being a hulking monster SUV today.

[1] which no SUV's nor trucks used as passenger cars, do because they are classed as 'utility vehicles' and have lower safety/fuel economy standards -- which is why the auto-makers went whole-hog on making/selling them, it got their CAFE averages down artificially.

In Japan there's a subset of cars called Kei or small cars, and they're very popular due to the lower tax, initial cost, fuel consumption and ease of parking.

In states of Australia registration is more expensive depending on the amount of doors and cylinders your car has. This doesn't seem to stop big cars being popular though, the #1 selling car in Australia is the Ford Ranger (which is BIG in Australian car standards). We're working on getting F150s sized vehicles even more heavily taxed, they aren't seeing wide adoption here and they're pretty highly criticised.

In cities like Rome you can see many small cars due to the nature of their streets and parking.

For highway driving these cars are a bit less comfortable but honestly modern Kei cars aren't even that bad. The Fiat 500 isn't a Kei sized car but it is also a very reasonable highway and city car, it can happily do both.

It’s going to have to be sorted at the DMV.

You take a defensive driving course, I’ll let you drive a tank down the road. But my neighbor’s kids should not be behind the wheel of a death dealer. Those vehicles were meant for skilled laborers, not Sally who is on her phone while driving.

Maybe... I think it would definitely help. I think just driving a smaller car that puts you in control might cause a lot of people to switch. I know that when I've done the opposite; gone from a very performance oriented car to a random person's SUV, I've felt extremely unsafe comparatively in breaking, merging, changing lanes, parking, etc. etc. I think most people just have little experience to compare it to anymore.

I also think it's odd that people don't already choose other options w/o a tax in place, considering the price of a bigger vehicle is almost always just going to be higher because of materials and a bunch of other factors.