The Sierra Club has named the Silver Line, the Purple Line and Capital Bikeshare as among the 50 best transportation projects in the nation.

The November report by the Sierra Club praises Metro's Silver Line and the Purple Line, neither of which is actually operating, for their potential to reduce the number of cars on the road and for inducing pedestrian-friendly development adjacent to their stations. The first phase of the $6 billion Silver Line is under construction and is set to open in late 2013. Work hasn't even begun on the Purple Line, which would connect Prince George's County and Montgomery County. It still needs more than $2 billion in funding.

The environmental group also praised Capital Bikeshare for eliminating 5 million miles of driving in 2011.

"The program encourages smarter transportation use in the city, easing air pollution and promoting healthy lifestyles by providing a convenient way to get around the city," the report said.

The Sierra Club also named the Outer Beltway, U.S. Route 460 and the Coalfields Expressway -- three potential Virginia projects -- as among the worst transportation endeavors in the United States.