This becomes a self-reinforcing cycle. If there are 7000lb passenger trucks on the highway around my compact car, I maybe start wanting to get a larger vehicle myself to protect myself from the idiots who drive them.
There has to be some sort of incentive either for smaller cars or against larger cars. Currently you can go into a dealer, tell them you want the biggest baddest truck/SUV that they have, and buy it all while having a normal license.
You'd only be paying a slight premium on whatever road or fuel tax if that while having the benefit of not getting destroyed in a car accident. As it stands, there is little reason to buy a larger vehicle unless you actually don't like driving a car that big.
Easy. Slap on an annual registration fee directly proportional to weight. Shit, just make it half the sale weight of the car for any non-EV, and half that again for EVs. Peg the ratio to inflation after that.