Gap Between Advertised And Real World Fuel Economy Doubles In A Decade

On some level, we all know that automakers advertised fuel economy numbers are a bit…optimistic, shall we say. So while there may be a glut of 40 mpg compact cars on the market right now, there has been some hearsay that the real world numbers rarely align with the advertised numbers, no matter how catchy the slogan used to sell them.

Now a new study done on European cars shows that the gap between advertised fuel economy and real world numbers has more than doubled, from 8% in 2001 to 21% in 2012. The study collected information from 28,000 user-entered entries in a German fuel economy database Europe has been implementing greenhouse gas reduction targets for decades, though they have become increasingly onerous in the last ten years.

The study uses CO2 emissions to factor average fuel economy, and what they found is that in the real world, vehicles were about 21% less-efficient than advertised. As I said, I think we all, on some level, realize that the advertised numbers are a bit generous. Over in Europe though, the study slams automakers and government officials alike. The paper says there is a high tolerance for exploiting loopholes and running fuel economy tests under impossibly optimistic conditions (flat roads, cold-start testing, no air conditioning on). The study also says the NEDC road testing standards are insufficient and do not represent real world driving conditions.

Automakers naturally want to tout high fuel economy at a time of high gas prices. However, it seems there is a lot of voodoo at work when it comes to achieving these impressive numbers…and it isn’t just a problem in Europe. Hyundai has been sued by consumer groups for misleading customers on fuel economy in the U.S., and Honda has just settled a lawsuit with Civic Hybrid owners who saw half the advertised fuel economy in the real world.

In other words, take any advertised fuel economy with a healthy spoonful of salt. You, the driver, are the most important factor in determining your overall gas mileage. On the same token, it’s kind of crappy how the government knowingly lets automakers lie to the car-buying public. Just another example of corporate cronyism run amuck.

Source: Green Car Congress | Image:Fuel Gauge via Shutterstock

Christopher DeMorro

A writer and gearhead who loves all things automotive, from hybrids to HEMIs, can be found wrenching or writing- or else, he's running, because he's one of those crazy people who gets enjoyment from running insane distances.