Like HowStuffWorks on Facebook!

10 Ideas for a Green Transportation Infrastructure

Subways Are Clean

Sure, anyone who rides the New York City subway -- or those in a lot of other cities, for that matter -- everyday will probably snicker (or worse) at the categorical statement that subways are clean. But while some individual subway cars and buses could use a good cleaning, the reality is that these modes of public transport take a heck of a lot of cars off the road and contribute mightily towards a greener planet.

Indeed, according to the Sierra Club, seven of the 12 cities with the best grades for smog-creating car and truck emissions -- places like San Francisco and, yes, New York -- are in states that spend the most on public transportation. Furthermore, the Center for Transportation Excellence reports that subways and buses are a major factor in fighting respiratory illnesses caused by pollution. Indeed, the center says that the bus and subway ridership results in 156 million pounds (70,760 metric tons) of the nitrogen oxides that cause respiratory disease from being emitted, which is to say nothing of the benefits in preventing the output of hydrocarbons that create smog and carbon dioxide that contributes to global warming.

Click on to discover why being “smart” underpins most of our choices about green transportation infrastructure.