EPA tests hurts hybrids like the Toyota Prius

Tailpipe SmogYour drive to work is a pleasure, uninterrupted by traffic or red lights, right? If not, perhaps you should work for the EPA, the Environment Protection Agency. These are the people who design the test cycles in order to generate the fuel efficiency ratings for each vehicle sold in the United States. Someone there felt that it was good idea to include just a single stop when measuring a car's fuel efficiency in the city. I can only assume their drive to work is a breeze. The result is that hybrid electric cars like the Toyota Prius and the Chevy Volt are not given any credit for fuel saved when their engines are turned off in traffic.

What Does That Matter?

The EPA’s flawed testing methodology is holding back the spread of hybrid vehicle technology. We tend to look at hybrid cars as a complex series of electrical and mechanical systems. They are complex, but there are some elements that could trickle down to the larger, non-hybrid fleet. One of these features is called stop-start, where the engine turns off when instead of idling. Such systems are rapidly gaining popularity in a whole host of Japanese cars, yet outside of hybrids, this feature is virtually non- existent in the United States. The reason is that the EPA city mode test gives virtually no penalty for fuel wasted while idling. Whereas the Japanese cycle shows at least an 8% improvement when a stop-start system is installed the US cycle only credits .2 miles per gallon at most.

It's Not Just A Number

You may be thinking, "So what, what does it matter, the EPA rating is just a stupid number on the window sticker and some mouse print on a television ad." That is not how the manufacturers see it. They are not as much concerned about how their prospective customer’s impression of a vehicle’s fuel economy as they are meeting ever increasing standards set by the EPA. These standards are set to rocket from 27.5 miles per gallon in 2010 (averaged across vehicles sold by each manufacturer), to 39 mpg in 2016.

Manufacturers are scrambling to eek fuel efficiency out of each new car design in order to meet this standard, yet systems that provide real world savings are being ignored because of a faulty grading system.  In Japan, stop-start is a $500 option on most cars. Since it could increase their fuel economy rating by 2-3 mpg at a relatively low cost, every car sold in the United States would soon have this system if the EPA would just give them credit for the real world fuel savings. The EPA is acting like a writing teacher who doesn’t give his students credit for proper spelling or grammar. They may give the student a passing grade, but the results will be substandard.


The car version of the educational conundrum of teaching the test.