I don't support a tiered system for firearms unless there's also a tiered system for voting.
However, a tiered system sounds good for driving. The current license would allow someone to operate an automobile with up to 150 hp. A vehicle with more than 150 hp would require a high performance endorsement, like for airplanes. Driving a pickup truck in counties with a population over 500,000 would require a separate test to show they can turn on city streets without a lane violation, and park within the lines of a single space at Walmart. Any collision would require a license retest. Two moving violations within 18 months would also require a retest. If they fail a retest, they have to wait 30 days to try again. In the case of hardship conditions, they can apply for a restricted license which allows them to operate cars with less than 100 hp during daylight hours, or directly to and from work or school at night.
It's for the children!