Trains vs. Planes vs. Automobiles
Is it always greener to take public transportation?
* Correction, Nov. 25, 2008: This article originally misstated the relationship between the emissions produced by Caltrain and those produced by a sedan. The train generates less than half as many greenhouse-gas emissions or particulate matter per passenger mile as a sedan, not less than twice as much. (Return to the corrected sentence.)
Jacob Leibenluft is a writer from Washington, D.C.
Photograph of the D.C.-area Metro train on Slate's home page by Win McNamee/Getty Images.