EPA tests are conducted under controlled conditions, not reflecting wind resistance or any accessories such as A/C. "Toyota Motor Corp., maker of the gasoline-electric-powered Prius hybrid, was one of the companies seeking the new tests after becoming concerned that customers felt deceived by the EPA mileage claims for the car." "The EPA currently relies on a standard series of indoor lab tests that simulate driving in mild weather at top highway speeds of 60 mph and average speeds of 48 mph. Vehicles are mounted on dynamometers — machines that spin their wheels to calculate mileage. The EPA acknowledges that the tests simulate driving conditions that are less severe than what most drivers encounter." http://www.latimes.com/classified/automoti...ieds-autos-news
Seems like a step in the right direction. personally, i'd love to see a list of the effects of those "power hungry accessories" on MPG. in other words, have something that says "AC on average will decrease mileage by 1 MPG" or whatever.
The estimate system will never reflect real-world if all they ever plan to deliver is just 2 numbers. Never taking into account below-freezing temperatures is one of many gross oversights, causing very misleading conclusions to be drawn.
Toyota says the Prius will get 48MPG (city) under the new EPA system. This seems like a large 20% drop versus other vehicle which will experience less of a drop until you consider the MPG myth (for you newbies). The myth is: "MPG is a linear scale". It is NOT, but a 1/x equation. Going from 60 MPG to 48 MPG "-20%" is only 125 gallons of gas difference a year over 30K miles. Do note the Prius itself doesn't actually change in consumption, just what the EPA reports. For a normal other vehicle, going from 24MPG to 22MPG, an "-8%" difference, is a 340 gallons of gas difference a year over 30K miles driven. How does that translate for your pocket book? $387.5 vs $1054 for $3.10 regular. Now, how does that 20% versus 8% look?