US Can Drive 55—and Should, Greens Say

Escalating fuel prices and fear of global warming are rekindling debate over the nation's maximum speed limit—and environmentalists are urging Congress to slow the US back down to 55 mph, Wired reports. Advocates say going back to the speed limit set during the oil crunch of the 1970s will allow cars to get better gas mileage and emit less carbon dioxide, while skeptics say the benefit would be trivial.

The US Department of Energy notes that gas mileage drops above 60 mph, and every 5 mph after is equivalent to tacking another 20 cents onto a gallon of gas. "Sheer physics tell you lower speeds equal better fuel economy, fewer injuries and lower emissions," says an executive at AAA. He notes another factor: "Doing 60 mph in a 2008 vehicle feels a lot different than in the vehicles our grandparents drove." (More cars stories.)