Back in December, we told you about the new method the government would be using to calculate fuel mileage. For the first time in twenty years, they decided to make changes to better reflect real-world driving conditions and driver behaviors. The changes went into effect starting with 2008 model year cars, and are evident in the newly styled window stickers on those vehicles (shown above). We correctly surmised that most estimates would go down by some degree using this new formula. In our comments, many of you immediately noticed that this would unfairly bump some vehicles into the gas guzzler tax bracket. Apparently, you had reason to be concerned.

Revealed after some sleuthing by the boys at Dubspeed Driven, the EPA is still using the 1991 tax schedule and gas guzzler calculation method. That essentially means that the exact same car that skirted the gas guzzler surcharge last year, could be a scofflaw in 2008. Cars like a Nissan 350Z, for instance. It's combined 23.15 last year kept it out of the gas guzzler bracket, but under the new formula, it's a $1,300 offender at 21.15 mpg.

There's no mention anywhere on the EPA website about the new testing procedures or the fact that 2008 vehicles will likely be reporting lower mpg compared to 2007 Monroneys. Scared at the possible backlash when their vehicles appear to be getting poorer mileage, major carmakers have banded together to create a website to help educate consumers about the apparent drop in fuel economy, but nothing seems to be in place at the EPA to account for the change. Trucks, some sport utilities and minivans are all still exempt from gas guzzler tax, however.

[Source: Dubspeed Driven]