Cyclists thrive where autos rule: Los Angeles, where smog and freeway have hitherto defined a lifestyle.

"The National Aeronautics and Space Administration has a 'critical responsibility' to the flying public to develop environmentally responsible solutions to the nation's most pressing aviation problems, NASA Administrator Charles F. Bolden Jr. said Wednesday."

"If the Chevy Volt's $40,000 price tag sounds a bit too steep, you could always go the do-it-yourself route of Oregon teenager Ashton Stark. He just finished a yearlong conversion of his grandfather's 1972 Volkswagen Super Beetle into an electric car."

"Each year, around a half a million people go whitewater rafting in Colorado, and the industry is a key economic driver in many rural towns. But in recent months, the issue of rafting and who can float through stretches of private property has divided the state."

"It's simply known as 'the wall,' a steel-and-concrete structure costing about $22 million that will be pounded deep into the floor of the Elizabeth River near one of the worst toxic-waste sites in Hampton Roads."

"The Army Corps of Engineers wants to use ash cast off from coal-fired electrical generation to shore up dozens of miles of Mississippi River levees, drawing fire from environmentalists worried that heavy metals from the filler might make their way into the river."

"U.S. EPA Administrator Lisa Jackson on Wednesday declared the entire concrete-lined Los Angeles River channel 'traditional navigable waters,' a designation crucial to applying Clean Water Act protections throughout its 834-square-mile urban watershed."

"Canada, which has a disputed sovereignty claim to the Northwest Passage, will require all larger ships plying the Arctic sea route to register starting on July 1, the government said on Tuesday."

"Billions of dollars of new business and tens of thousands of jobs will flow to four hub cities -- Los Angeles, Chicago, Orlando and Albany, N.Y. -- where plans for major high-speed rail networks are located, according to the U.S. Conference of Mayors."