Cliff metaphors abound these days, thanks to our members of Congress. In my travels, I've run across the deportation cliff, the human cliff, and yes, the transportation cliff. (Thank you, Rep. John Mica, R-Fla.). To be clear, there are two cliffs in the transportation world. There is the "fiscal cliff," which would result in an overall cut of about 8 percent in federal funds. That impact on transportation isn't clear, although it would certainly be a blow. The National Air Traffic Controllers Association says that could result in a furlough of 2,000 to 2,200 air traffic controllers, which could ultimately result in fewer flights.