1987 Chevy Silverado 4 X 4, Clean Florida Truck, 95k Miles / Ac 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.

Weekly Recap: Revisting the BBC report that ended Jeremy Clarkson's Top Gear run

Jeremy Clarkson's long run as a Top Gear host has come to an end, and the reason is clear: His physical assault on one of the show's producers crossed a line, and the government-owned BBC couldn't tolerate it. The incident between Clarkson and Top Gear producer Oisin Tymon was initially described as a "fracas," and Clarkson was suspended. But his popularity and widespread support – even British Prime Minister David Cameron weighed in – suggested that the controversial Clarkson might be given yet another chance. The BBC put this to rest Wednesday when it sacked Clarkson and revealed the findings of its investigation. The report spelled out how Clarkson struck Tymon on the patio of a North Yorkshire (UK) hotel, leaving him with a bloodied, swollen lip. It was severe enough that the producer sought medical treatment. During and after the attack, Clarkson shouted expletives at Tymon and threatened to fire him. The noise carried into the hotel's dining room and even to a bedroom. Local police investigated the incident, but Tymon isn't pressing charges. The huge audience numbers, Clarkson's popularity and the high-octane excitement of Top Gear all melted away in the eyes of BBC director-general Tony Hall, who saw an attacker and a victim. "For me a line has been crossed," he said in a statement. "There cannot be one rule for one and one rule for another dictated by either rank, or public relations and commercial considerations." In that moment, Clarkson was the bad guy, though he was actually the one who reported it to the network and made repeated attempts to apologize to Tymon. He's also urged the media to leave the producer alone. Hall voiced regret in the statement that announced Clarkson's contract would not be renewed, but the BBC decided to move on. Rumors are swirling about possible replacements for Clarkson. The network says it wants to continue Top Gear in 2016 and is looking to air the rest of this season's episodes. Despite the controversy, the show has a global audience of 350 million viewers and is one of the BBC's most valuable properties. It's unclear what Clarkson's co-hosts, James May and Richard Hammond, will do, as their contracts were also reportedly up to be renewed. Other News & Notes 2016 Chevrolet Malibu hybrid charges up with Volt technology Chevrolet is taking some of the learnings and technologies from the 2016 Volt and dropping them into the reborn Malibu hybrid.

Is the skill of rev matching being lost to computers?

If the ability to drive a vehicle equipped with a manual gearbox is becoming a lost art, then the skill of being able to match revs on downshifts is the stuff they would teach at the automotive equivalent of the Shaolin Temple. The usefulness of rev matching in street driving is limited most of the time – aside from sounding cool and impressing your friends. But out on a race track or the occasional fast, windy road, its benefits are abundantly clear. While in motion, the engine speed and wheel speed of a vehicle with a manual transmission are kept in sync when the clutch is engaged (i.e. when the clutch pedal is not being pressed down). However, when changing gear, that mechanical link is severed briefly, and the synchronization between the motor and wheels is broken. When upshifting during acceleration, this isn't much of an issue, as there's typically not a huge disparity between engine speed and wheel speed as a car accelerates. Rev-matching downshifts is the stuff they would teach at the automotive equivalent of the Shaolin Temple. But when slowing down and downshifting – as you might do when approaching a corner at a high rate of speed – that gap of time caused by the disengagement of the clutch from the engine causes the revs to drop. Without bringing up the revs somehow to help the engine speed match the wheel speed in the gear you're about to use, you'll typically get a sudden jolt when re-engaging the clutch as physics brings everything back into sync. That jolt can be a big problem when you're moving along swiftly, causing instability or even a loss of traction, particularly in rear-wheel-drive cars. So the point of rev matching is to blip the throttle simultaneously as you downshift gears in order to bring the engine speed to a closer match with the wheel speed before you re-engage the clutch in that lower gear, in turn providing a much smoother downshift. When braking is thrown in, you get heel-toe downshifting, which involves some dexterity to use all three pedals at the same time with just two feet – clutch in, slow the car while revving, clutch out. However, even if you're aware of heel-toe technique and the basic elements of how to perform a rev match, perfecting it to the point of making it useful can be difficult.