MPG estimates: trust automakers?

I apparently can't rely on the EPA estimates for MPG when we start looking at hybrids and especially at plug-ins. Basically no one knows how to measure if we're really making an earth-friendly choice when we're comparing close options like Toyota's Prius hybrid vs. Toyota's Yaris conventional high-mileage compact car (it's not a random comparison, I'm actually debating between the two!). No debate that a Prius vs. a full size SUV is an easy choice.

This article makes me uneasy... the quote I pulled out below is from Matt Mattila, "a consultant for the Rocky Mountain Institute's Project Get Ready, which helps cities prepare to adopt electric vehicle technologies," who suggests we should let the autmakers be our source of information. Without scientific confidence in EPA's estimates, I guess that is what is happening now! The problem, extended to all the new green technologies that could be coming out, could lead to FUD (Fear Uncertainty Doubt, a tactic perfected by Microsoft) and inaction on the part of consumers.

Great expectations -- a dickens of a problem for plug-in hybrid electric carmakers
By JESSICA LEBER, NYTimes, April 22, 2009

"Mattila said that it is up to the automakers to educate consumers that the plug-in hybrid will not be the right option for everyone, and that whether it is right for them would depend on their driving patterns.

"The car companies are blunter: "The real question is, can we get anyone to buy it?" asked Stricker. If the fuel saved with a plug-in hybrid compared to a conventional hybrid doesn't outweigh the added cost -- and with the price of batteries, that added cost is significant -- then no one will buy the car."