Conspiracy theorists have long insisted that automakers could push their vehicles to achieve better fuel economy, and as it turns out, they were right. Of course, it isn't as easy as flipping a magic MPG switch, but automakers are making incremental gains on vehicles even between redesigns. Techniques like changing gear ratios, lowering revs at highway speed and using lower rolling resistance tires are helping drive up efficiency a few percentage points at a time.

In light of the current pain at the pumps, fuel economy is on all of our minds these days no matter what kind of car you drive. That being the case, it might not be surprising to you that the car we're buying are getting more fuel efficient. Don't believe us? The National Highway Traffic Safety Administration has just revealed that the U.S. auto industry set a new record in overall fuel efficiency during the first half of the 2008 model year by averaging 26.8 mpg through March. That's up from an average of 26.6 mpg through the entire 2007 model year.

As if "shift lights" weren't annoying enough... Nissan's new "ECO pedal" has been engineered to encourage good fuel economy with a servo-actuated gas pedal that will push back on the driver's lead foot when on-board computers detect wasteful acceleration. According to Nissan, vehicles equipped with the ECO pedal, and real-time fuel consumption gauges in the instrument panel, have returned a 5-10 percent increase in fuel efficiency. The Japanese automaker says it has plans to begin installing the ECO pedal in models next year, although there is no word on what models, or markets, will get the system. We're betting it's an option unlikely to show up on the GT-R anytime in the near future.

[Source: Reuters]

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Click above for high-res gallery of the Toyota Prius

If the Prius went mainstream when Toyota bumped production to 280,000 worldwide units per year in 2007, the fuel efficient hybrid is now primed to kick project green to the next level. When Toyota begins producing the next gen Prius, it'll do so with more factory space than ever dedicated to the universal symbol for fuel efficiency, making it possible to produce 480,000 vehicles per year. The Japan-based Tsutsumi factory, which currently builds five different vehicles, will stop making the JDM Wish minivan to allow for more Priuses. Even more Prius capacity will be available beginning in 2010, when the Japanese automaker's new Mississippi plant comes online and begins to produce more of the hybrid.

The already fuel efficient Smart fortwo will soon become even more stingy with the petrol when start-stop technology is employed fleet-wide beginning in October. The start-stop technology, which is called "micro hybrid" by Smart, works by cutting off the engine during braking when the vehicle speed drops below five mph. According to Smart, the engine restarts immediately when the brake is released and the technology will result in a fuel savings of 8 percent, bringing consumption in the US EPA cycle to about 44 mpg on the highway and 36 mpg in the city. CO2 emissions will also be reduced by 9g/km, now netting 103g/km. The technology will also be available on the CDI Smart when it hits production next year, but as of right now, the diesel fortwo isn't coming Stateside.

These days it seems more common to overhear comments about a particular car's appalling fuel economy than idle chatter about the weather, which makes sense when a gallon of gas costs as much as a cheap umbrella. For instance, just the other day there was some guy going on about how his car was getting 3 mpg less than just a few months ago and had no idea why. That is until it was pointed out to him that his car's adjustable luggage rack was in its full, upright position, giving his car the aerodynamic efficiency of a cinder block.