This week at TreeHugger: Love it or hate it, the niche for green muscle trucks is being filled. Does a biodiesel Hummer make any sense? Who decides? Readers got more than a little rankled at the thought, so we threw it open to a vote. Biofuels, for all their carbon-neutraly goodness, emit nitrous oxide (no, it doesn't make the car go faster). But which biofuels emit the least of this smog fog? Using no gas at all, Popular Mechanics gets a chance to goof around with the Mullen L1X-75 electric supercar from Hybrid Technologies, while A123's electric motorcycle clocks in at 155 mph, breaking the electric bike speed record for the quarter mile. What the X-Prize did for commercial space flight, the Automotive X Prize hopes to do for the clean cars of the future. Preliminary guidelines were released this week at the New York International Auto Show. Chevy's new minicar will be efficient, slick, and small. But which of the three designs will they choose? Go to their site and vote for your favorite body (or pseudo-hipster name). Toyota's hybrids are flying off the lots like hotcakes and March was the best month yet. But the company's new Tundra monster earned it some major flak at the NY Car show. In Japan they call it nenpimania: the obsession that grips Prius drivers to hack their cars and achieve unworldly gas mileage.

[TreeHugger's Perspective Shift roundup appears every Wednesday]