> My nose for unintended consequences says manufacturers could start selling cars with worse tires to bring down the average.

They won't want to do that because it'll hurt their advertised mileage/range.

This is aimed at the different incentives between selling tires to manufacturers (make sure mileage is good, balance that against raw cost) vs direct to consumers (up front cost is king).

There are doubtless still some potential loopholes that will be explored, though some of the most obvious (like reducing tread depth, mentioned here, appear to have been considered already: https://www.roadandtrack.com/news/a71509031/california-tire-... ). It doesn't appear to be that naive.

It's also something that's hard to find info on when shopping for tires, so more transparency should help consumers.