American drivers of new cars emit 22% less CO2 that 6 years ago. What happened?


After almost three decades of stagnancy US fuel economy is finally on the move.  Its actually quite something.  Fuel consumed peaked in 2004, miles driven in 2006 and vehicle numbers topped out in 2008.  Could motorization in the US of peaked?  That’s a tough one, but emissions driving emissions may well have.

What we do know is that the last time we saw this type of improvement was when the Iranian Revolution resulted in 4.5 million barrels of missing production.  In the image above we can see that fuel economy was stagnant for decades as all engineering improvements were eroded by American’s buying bigger and bigger cars.

So what’s has finally changed?  Was it the recession?  It may have played a part, but it certainly isn’t the whole story.  First let’s unpack that headline.  A 22% reduction in emissions in six and half years is quite something.

Eco Driving Arrives in America

The University of Michigan does some epic number crunching on US fuel economy which they keep in the form of the Eco Driving Index. The total EDI for vehicle emissions tells use that an American driver of a new car in March 2014 generated 22% fewer emissions that a similar new driver in October 2007.


Happily the index is comprised of two sub indexes, allowing us to separate the effect of changes in distance driven and fuel used. From this we can see that the big change is improving fuel economy, with new cars requiring 19% less fuel to cover the same distance as in 2007.  Distance driven is off 4%.

Below is a chart the sharp rise in fuel economy of new cars (adjusted to window sticker ratings).

MPG march 2014So what happened?  Given that the economy is up significantly since the crisis and mileage only down 4% its tough to say how big a part the recession had.  It could have helped to skew purchases towards more economic cars, but I prefer the following two explanations.

Obama’s Quiet CAFE Revolution

Everyone knows the EPA under Obama has been grinding up the corporate average fuel economy (CAFE) standards.  It’s not got the column inches of the power regulation proposals of late, but the effect will be profound.

Here’s a chart showing the ramp up:

Cafe Standards

The Third Oil Crisis

Okay, no one actually calls it this.  Krugman jumped the gun in 2002. But we were so busy with global financial crisis a few years back that no one bothered to get excited about it rising oil prices.

Just indulge me a little. Look at this chart:

The third oil crisis The 11% decline in US oil consumption from 2005-2012 does not match the 19% drop from 1978-83, but it dwarfs anything else in the last 40 years.  This graph actually looks like it’s straight out of Econ 101.  Stick the price up, we’ll consume less.

So there you go.  Three potential ideas for why American’s are finally finding their love of fuel economy.

What do you think?  Anything else going here?

  • Randy

    I recently moved to Poland and I love the public transportation in Warsaw. I take electric trains to the city center, where I ride electric trams or subway trains. I avoid the diesel buses. Why aren’t they electric yet??

    The US should be connected with trains like Europe is. That should have been the stimulus program, building rail. Stop subsidizing houses, instead tax them, fuel, and ICEV. Build public transportation. All the rails should be upgraded to electric too. Also throw in a new grid. 😉

    • jeffhre

      The US? It is, has been, uh, was? Well, take a look, from Wikipedia.

      Pacific Electric, also known as the Red Car system, was a privately owned mass transit system in Southern California consisting of electrically powered streetcars, light rail, and buses and was the largest electric railway system in the world in the 1920s. Organized around the city centers of Los Angeles and San Bernardino, it connected cities in Los Angeles County, Orange County, San Bernardino County and Riverside County.

      Throw in all the abandoned street cars, nationwide, and there you have it. Google Standard Oil, GM, Firestone conspiracy, if you’d like to round it all off with frosting on top.

  • Randy

    Aww you dont have Poland on your carbon calculator :( I wanted to see how it has changed

    • Lindsay Wilson

      The calculator needs some work once I get this video project sorted. How’s Poland treating you? Quite a switch! Poland’s emission per capita are about average for Europe (9t), but it has the highest carbon intensity (0.8 kg CO2/$). The problem is all the coal fired electricity, I think only Estonia has dirtier electricity in Europe. If they sorted that out they’d be doing well

      • Randy

        I love it here. But I’m disappointed that the incandescent bulb is still popular here. In the US, a local utility subsidized CFLs. I could often get 3 or 4 for 98 cents. I bought over 1000 of them and gave them to family, friends, some groups, etc. I thought that was a better thing to do than buying carbon offsets. Also bought over 100 LEDs.

        I also got to ride a train, a bus, and a tram for the first time! I also rode the subway, which i only did with a school group in DC. I try to avoid the bus, it uses diesel, I like the electric! 😉 Though I do wish Poland would go away from coal.

        I would assume the trains use regenerative braking to get a lot of the energy back. Do you know if this is the case? I couldn’t imagine why not.

        I’m currently living with a family so I’m not taking im more space, to have my own place, so thats good. I think my footprint has probably shrank considerably here, actually. I used the “UK” calculator on here and adjusted the impact numbers to get a rough estimate. Is there any way I can help with anything?

        • Lindsay Wilson

          I’ll build a European calculator at some point. Then you can get a half decent idea just be tweaking the electricity intensity. As an Aussie living in Europe I just adore the trains. They are better than air or driving for emissions and such a lovely way to see Europe, particularly once you are on the high speed network. All good here, loads of videos coming up!

          • Randy

            I have only ridden on local trains so far. I want to ride a train to Berlin though.