7 Most Popular US Light Rails (PHOTOS)

A light rail is an urban mode of public transportation that generally has a lower capacity and speed then heavy rail and metro systems. Light rails most often feature electric rail cars that operate separate from street traffic, but are occasionally integrated on the roadways.

With a growing need for better and more efficient public transportation to help reduce our carbon impact, light rails are increasing in popularity across America. As people look for alternatives to cut down on oil consumption in response to the gulf oil spill, HuffPost Green wants to celebrate some great light rail systems we've already got in here in the US. Here are the 7 most heavily used light rails in the country, according to the American Public Transportation Association's Public Transit Ridership Report from the fourth quarter of 2009.