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This map reveals the cleanest vehicles based on location

Naysayers love to point out how dirty the electricity grid mix is when it comes to charging electric vehicles. Curmudgeons are eager to jump into any conversation about EVs to enlighten the lucky listeners about how plug-in cars contribute to pollution, sometimes even throwing in a dash of climate-change denial for good measure. (Thanks, buddy. Pray, tell me more about the plight of oppressed SUV owners.) Unless someone buys an EV just because they think they're cool (which, yeah, they often are), they probably have at least a passable understanding of their environmental pros and cons. As many EV owners are already aware, location has a lot to do with any particular plug-in car's carbon footprint. Still, there's always more to know, and knowledge is not a bad thing, especially if one uses it to do the right thing. That's why this handy-dandy map from Carnegie Mellon University is so interesting. CMU researchers have compiled information about the lifecycle greenhouse gas emissions of various EVs based on where they're charged, as compared to gasoline-powered vehicles. The researchers looked at the Nissan Leaf, Chevrolet Volt, and Prius Plug-In Hybrid versus the gasoline-dependent Toyota Prius hybrid and the stop-start-equipped Mazda3 with i-ELOOP and compared grams of CO2 emitted per mile. CMU takes into account the grid mix, ambient temperature, and driving patterns. CMU takes into account the grid mix based on county, as well as ambient temperature and driving patterns in terms of miles traveled on the highway or in the city. For instance, if you drive a Nissan Leaf in urban areas of California, Texas, or Florida, your carbon footprint is lower than it would be if you were driving a standard Toyota Prius. However, if you charge your Leaf in the Midwest or the South, for the most part, you've got a larger carbon footprint than the Prius. If you live in the rural Midwest, you'd probably even be better off driving a Mazda3. Throughout the country, the Chevrolet Volt has a larger carbon footprint than the Toyota Prius, but a smaller one than the Mazda3 in a lot of urban counties in the US. The Prius and Prius Plug-In are relatively equal across the US. Having trouble keeping it straight? That's not surprising. The comparisons between plug-in and gasoline vehicles are much more nuanced than the loudest voices usually let on.

Honda, Mazda, Mitsubishi, Mercedes also under diesel emissions scrutiny

The controversy over Volkswagen's diesel emissions scandal isn't limited to the US. In Europe, where diesel engines are far more popular, the issue is shining a harsh light on the NEDC emissions test. As already known, the evaluation does a poor job of reflecting real-world production of NOx, and it appears a significant number of automakers are affected. The Guardian in the UK has been reporting on real-world test results from a company called Emissions Analytics. After the latest round of checks, vehicles from Mercedes-Benz, Honda, Mazda and Mitsubishi were found to generate far more NOx than they should. The newspaper also published similar results for Renault, Nissan, Hyundai, Fiat, Volvo, Jeep, Citroen, VW, and Audi. On average, the figures are about four times over the limit of producing the pollutant. Unlike VW and its defeat device, these automakers aren't actually breaking the rules. The vehicles perform up to the NEDC lab test for emissions, but those results simply aren't translated to the street. "The VW issue in the US was purely the trigger which threw light on a slightly different problem in the EU - widespread legal over-emissions," Nick Molden from Emissions Analytics said to The Guardian. A big fight to decide the future of this issue appears to be on the horizon. Automakers claim that they can't meet the next round of tightening emissions regulations and are asking for compromises. Although, spokespeople for Mercedes and Honda told The Guardian that the brands would be in favor of the stricter rules. Meanwhile, some European governments began backtracking their support of diesels well before this scandal came to light. The added scrutiny certain hasn't helped the future of the oil-burner. Related Video:

Mazda returning to top-tier racing with diesel-powered prototype in USCC

Mazda has unveiled its latest challenger in the top flight of endurance racing, a diesel-powered prototype that will campaign the inaugural, 2014 Tudor United SportsCar Championship. The new Skyactiv-D-powered car will make its race debut at January's Rolex 24 at Daytona.
"This is the most significant step Mazda has taken towards returning to the global racing stage since our overall victory at Le Mans in 1991," said the director of Mazda Motorsports, John Doonan. That historic racecar, the rotary-powered 787B, has grown to become one of Mazda's many, well-known racers.
More recently, the Japanese brand has been making waves in the Grand-Am series, campaigning RX-8s and, most recently, running diesel-powered Mazda6 sedans in the GX-class. Mazda will campaign two factory-backed prototypes at Daytona. Driver lineups will be announced closer to race day.