Tuesday, August 9, 2011

Transportation Modes

Transportation statistics, published by the Bureau of Transportation Statistics, tend to lag reality by several years—echoing, perhaps, the broad public interest in this fundamental economic activity. The public’s eyeballs are on cell phones and pads, not on the big roaring trucks—and the near-invisible barges and rails. Today I present some data for 1993 and 2007—and 2007 seems so yesterday, doesn’t it. But the trends are important. And with minds now focused on the ephemeral (the Dow, the Debt Limit), it might be a nice moment to remember that some 12.5 billion tons of goods are moved in this country every year—by trucks, rails, barges, air, and pipeline—and that this tonnage is moved a staggering 3.3 trillion ton-miles. A ton-miles is one ton moved one mile, and the huge figure therefore suggests that on average every ton of freight moves nearly 267 miles.


This graphic shows the shares, in percent, of total tonnage moved in 1993 and in 2007, by modes of transport. The dominant transportation here, based on weight alone, is intercity trucking. It commanded a 70 percent share of all tonnage. Note, please, that every other mode, with the exceptions of pipelines and multi-mode transport, lost share to trucking. The difference between Trucking and the nearest other mode, Rail, being a huge difference of 55.2 percent tells us that, for all practical purposes we transport everything by truck. But in the transportation sector a more meaningful measure is the ton-mile, fusing both weight carried and distance.

Most freight classified as “multi-mode” falls under parcel deliveries by freight services or the Postal Services. Another instance would be rails carrying already-loaded trucks. “Unknown mode” means that the U.S. Department of Transportation had real data on hand but not enough information to classify the transporation system used by mode of carrier.


What we note in the second graphic is that trucking and rail are close to equal in their share of ton-miles. Indeed, rails just beat trucking by a very slender 0.1 percent. Data for pipelines, while BTS does have them, are not published because of high sampling variablity. The data shown account for 98 percent of total ton-miles in 1993 and 98.6 percent in 2007; the missing points are probably due to pipelines. The gain experienced by trucking that we see above, between 1993 and 2007, is greater than the gain experienced by rail. And most troubling is the more than halving of water-transportation’s share. Why does that matter? Well, in terms of energy consumption and environmental protection, the best mode of transportation is by barge, then by rail, and finally by truck. Therefore any gains by trucking represent a negative from a perspective of long-range sustainability. To be sure, commodities like grains, sand, rock, and liquids travel by water—and the loss of water-transportation’s share indicates and change in total consumption of goods. We move more manufactured and packaged than commodity goods. And the closer to sale the freight is (meaning ready to sell to consumers in a store) the more speed and time matter. And barges are slow.

In about four years or so—the Department of Transportation is as slow as the barges—I might be able to bring you numbers for 2011—but by that time 2011 will seem so yesterday.

The data source here is the BTS (link). Look for Table 1-52.

1 comment:

  1. Hurray for the lowly barge!

    You make an interesting point about the shift from commodity movements to finished goods movements. Of course, on the global stage I'm guessing we are actually moving a whole lot more on the water than ever before, what with globalization's rise. Once things reach our shores, however, we get them onto trucks quickly...

    And you're right, it is a fine time to focus on the basic industries that just keep plugging away as the stock market does its frenzied dance.

    Cheers!

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