2006 Mazda Mx-5 Miata Touring Convertible 2-door 2.0l on 2040-cars

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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.

Mazda's rotary engine may live on as a range extender (UPDATE)

Update: We received a response from Mazda that confirmed plans for a 2019 electric car available in battery-only and range-extended models, but there was no comment on any other details. The text has been updated to reflect this. It may be time for rotary fans to start getting their hopes up a little for a return of the spinning triangle engine. Automotive News spoke with Mitsuo Hitomi, the man in charge of Mazda powertrains, who said there's a very good chance the next implementation of the rotary engine will be as an electric car range extender. The news source also suggests that such a vehicle could be just around the corner, since Akira Kyomen, Mazda's vehicle development program manager, confirmed to Automotive News that the company will have an EV out in 2019 in both pure electric and range-extended versions. We reached out to Mazda for more information, and a representative confirmed both the pure electric and range-extended models for 2019, but couldn't comment on anything else regarding those vehicles. Looking back, we have reason to believe that this really might happen. As far back as 2013, Mazda was working on a rotary-engine range-extended electric car in the form of the Mazda2 RE Range Extender. It had a total range of 250 miles, half of which came from its battery, the other half from a 330 cc rotary engine generator fueled by a 2.6-gallon gas tank. More recently, Mazda has also teased rotary power with the RX-Vision concept at the 2015 Tokyo Motor Show and another rumored rotary concept at this year's show, which could be the design concept teased recently. But most convincing is the patent we found from Mazda that described a range-extended electric car that would specifically use a rotary engine. The powertrain layout looks just like the one used in that Mazda2 concept. There's also the fact that, as we've previously pointed out, and as Hitomi mentioned to Automotive News, the rotary could be a good range-extender due to its compact size and smoothness. Of course it also isn't known for being the most efficient engine, but if it isn't required to provide all the forward propulsion, it could be made small enough that it's frugal, and the added space and weight savings would be important for making the vehicle more practical, adding more batteries, or simply keeping the car lighter. This news might not excite rotary die-hards who have been waiting for an RX-7 and RX-8 successor, but they shouldn't quite abandon hope yet.

10 automakers shack up in Detroit hotel to talk Takata airbags

Since Takata has decided not to take the lead concerning potential issues with its airbag inflators, the automakers have. Perhaps that's unsurprising, since it's the automakers, not Takata, that will take a beating on the dealership floor if consumers decide its models are a health hazards. The Detroit News reports that Toyota, Honda, General Motors, Ford, Chrysler, Mazda, BMW, Nissan, Mitsubishi and Subaru met in a hotel conference room near the Detroit Metropolitan Airport last week to sort out a way to understand the technical issues involved. So far, faulty airbag inflators have been ruled the cause of five deaths and 50 injuries around the world, but neither Takata nor investigators understands exactly why the inflators are malfunctioning. The National Highway Traffic Safety Administration recently asked Takata to issue a national recall, Takata declined, citing a minuscule failure rate and the fact that it's still investigating the issue. Toyota and Honda then made an industry-wide appeal for "a coordinated, comprehensive testing program" that would pinpoint the problem inflators and get them replaced, and that's what the Detroit meeting was about. Numerous issues, however, will make this a long row to hoe: simply getting the parts to replace the nearly 20 million inflators in cars recalled around the world so far - even working with other suppliers - will take a years, but more importantly, no one knows if the replacement inflators currently being installed will suffer the same issue. Answers will hopefully come quickly with Takata, the ten automakers and NHTSA all independently investigating the problem.