Require a commercial license to drive large and/or heavy vehicles. Take away such commercial license when a driver gets caught driving unsafely.

This is my favorite type of suggestion because it puts the responsibility on the person driving and makes it clear that hauling heavy loads or large trailers is a bigger deal than driving a sedan. We have different licenses for motorcycles, the same makes sense for any light truck and above. This would also promote the use of compact sized trucks that are basically cars with beds and minivans instead of people getting full sized vans and massive trucks.