Hey, guess what. The feds just put the newest transportation statistics annual report up on the web (http://www.bts.gov/programs/transtu/tsar/tsar99/7chap05.pdf). No real changes. The trends are pretty stable from year to year. Only a relatively trivial number of people using transit, despite a large increase in the number of miles of service offered. For you environmental people out there, energy consumption per passenger mile continued to get better for autos (and even SUVs). Commuter trains are getting.worse, but still better than autos, once you ignore the energy costs of building the system to begin with. AMTRAK was actually pretty good, having eliminated some of their REAL loser routes. Of course, Greyhound is 40% of the energy cost of AMTRAK, and takes you to a lot more places. Transit buses? About the same as an SUV. A passenger air mile costs less than a transit mile in energy, about 10% MORE than taking the same trip by car.

If you believe in CO2 and global warming, the real problem children appear to be airplanes and transit buses.

With these caveats in mind, in 1996 passenger car energy intensity was about 3,700 Btu per passenger-mile, down slightly from 3,900 in 1990 and 4,200 in 1980. (Even though new vehicle fuel economy has leveled off, the entire fleet is still more efficient today than years ago, which indicates why energy intensity has declined somewhat.) Light-truck energy intensity was 4,529 Btu per passenger-mile in 1996, down from 4,859 in 1990 and 5,384 in 1980 (assum-ing the same occupancy rates as automobiles). Air carrier energy intensity was 4,100 Btu per passenger-mile in 1996 (versus 4,800 in 1990 and 5,800 in 1980) (Davis 1998). The decline in energy intensity of air travel is due largely to higher occupancy. Flying a full plane requires considerably less than twice the fuel of a half-full one, but yields twice the passenger-miles. Airlines have been increasingly successful in filling their planes. Some have even reconfigured seating to fit in more passengers. Newer airplanes are more efficient, but that probably has less effect on energy intensity than the greater number of pas-sengers sharing the fuel. If the economy declines, occupancy may drop and energy intensity rise (Davis 1998). Energy intensity of Amtrak trains was about 2,400 Btu per passenger-mile in 1996, down from 2,600 in 1990 and 3,200 in 1980. By contrast, energy intensity of rail transit (commuter trains and subways) actually rose from 3,000 in 1980 to 3,500 in 1990. Intercity buses show the lowest energy intensity, about 1,000. Transit buses are higher, at about 4,500 Btu per passenger-mile, as might be expected from their stop-and-go duty cycles (but transit bus data are particularly weak since passenger-miles are not automatically recorded with ticket sales) (Davis 1998).

-- Craig Carson (craigcar@crosswinds.net), January 13, 2000

Answers

Let's GET RID of the transit buses to decrease those carbon dioxide emissions. It's a sacrifice, but IT'S FOR THE CHILDREN!

-- (zowie@hotmail.com), January 13, 2000.

It's worth it to get rid of a thousand busses if it saves the health of ONE innocent child!

See, I've learned to use liberal-speak too. Great stuff, makes arguments MUCH easier!

-- Albert Fosha (AFosha@aol.com), January 14, 2000.