This article from Next American City looks at escalators -- the expensive, energy-intensive, and often under-used transportation mode.
"Their primary function is to move significant numbers of people from one floor to another in an environment where conventional staircases cause traffic jams, but most of the time, they are chronically underused."
"According to statistical findings attached to the Energy Efficiency Act, which became law in 2006, 90 billion people each year ascend and descend on escalators, making it a more popular form of transportation than commercial airliners. The national energy use of escalators is estimated at 2.6 billion kilowatt hours per year, equivalent to powering 375,000 houses; its cost is roughly $260 million."
"In order to cut down on wasted energy, Congress has been flirting with converting standard escalators into intermittent escalators, which run only when someone steps onto them. The Energy Efficiency Act calls for the installation of intermittent escalators in the Capitol Building, to set an example for the rest of the nation."