Today, we've got an update on Tesla's promised semi tractor, some real-world analysis of the possible impact of fuel-economy rules, and the start of our monthly report on sales of cars with plugs. All this and more on Green Car Reports.

Which is more important to the future of electric cars, China or the U.S.? We polled our Twitter followers—and their responses were conclusive.

The impact of delaying the last four years of fuel-economy rules won't be as great as some overheated rhetoric makes them out to be; we've already seen the biggest impacts since 2012.

Remember that Tesla semi truck? Elon Musk teased it at a TED talk, and that wasn't the only Tesla news he offered.

Sales results for April are starting to come in, and we've got the numbers in our monthly plug-in electric car sales report.

Tesla asked us to add a note to our recent piece on its addition of automatic emergency braking, and we felt the request was justified. Barely.

Lexus has trademarked the name for an LS fuel-cell concept, indicating that halo-car zero-emission luxury sedan may be on the way.

Finally, why some of you have to have your car smog-tested—and others of you don't.

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