More specifically: Will the average car sold in the US in 2030 be smaller than the average car sold (in the US) in 2025

“Carnegie Mellon University engineering professor Kate S. Whitefoot and University of Michigan engineering professor Steven J. Skerlos find that the footprint-based CAFE standard gives automakers an incentive to increase vehicle size and weight. They estimate that this increases vehicle size between 2% and 32%”

https://www.mackinac.org/S2022-06#overview-and-history-of-cafe-standards

As part of Trump’s Big Beautiful Bill the fee for exceeding CAFE standard was changed to $0.00, which removes the supposed motivation to increase vehicle size. Will this cause vehicles to get smaller?

Edit (2 Aug 2025): Trucks and SUVs will be counted as cars for this market.

Edit (4 Aug 2025): Footprint will be used to judge the change in size, not weight, unless someone was a good reason and method to do differently.