Americans are buying more fuel-efficient cars ...

Source: Know More
Source: Know More

But many countries are still way ahead ...

Source: Center for Climate and Energy Solutions
Source: Center for Climate and Energy Solutions

The two charts above, taken separately, could be somewhat confusing. Perhaps I can clarify.

The first chart, showing average sales-weighted fuel-efficiency, is less about individual consumer preferences than it is about manufacturers' average fleet efficiency since the government mandated higher standards. Overall, cars continue to become more efficient.

We can track U.S. heavy vehicle, SUV and truck purchases by monitoring the price of gasoline. Each spike in gas prices causes consumers to shift to smaller, more efficient cars. The shift is often temporary.

Americans don’t need gasoline prices to fall to start buying more SUVs and large trucks; the only thing required is stability at a given price point (e.g. oil prices holding between $95 to $105 a barrel). That stability leads to an uptick in sales of bigger vehicles and a stall in light-duty sales.

To contact the author of this article: Barry Ritholtz at britholtz3@bloomberg.net.

To contact the editor responsible for this article: Alex Bruns at abruns@bloomberg.net.