Transportation Energy Data
posted in Book reviews, Transportation, Useful Data |The Department of Energy has just published the 28th edition of the Transportation Energy Data Book, including data for 2007. Since this was the source of some of the Antiplanner’s data used to compare energy consumption and greenhouse gas emissions of cars vs. rail transit, it is worth taking a look to see what has changed.

Two of the most important pages contain tables 2.13 and 2.14, physical pages 64 and 65. These list the energy consumption per passenger mile of various forms of transportation between 1970 and 2007.
The tables indicate that, between 2006 and 2007, energy consumption per passenger mile of cars increased by 0.1 percent. For light trucks, it decreased by 0.9 percent, but for transit buses it increased by 1.3 percent. Airlines reduced energy consumption per passenger mile by 3.0 percent; Amtrak by 5.1 percent; and light/heavy rail transit by 4.8 percent. However, commuter rail energy consumption per passenger mile increased by 4.4 percent.
We have good data on the number of passenger miles and number of vehicle miles for Amtrak and various forms of transit, so we know that Amtrak and light/heavy rail became more energy efficient by increasing the percentage of seats they filled. This increase, in turn, resulted from high gas prices that led a small number of people to start taking public transportation.
We don’t have good data on occupancy rates for automobiles — the authors of the data base assume they have been fixed at 1.57 people per car and 1.72 people per light truck since 2001, when the last National Household Transportation Survey was done. In reality, it is more than likely that families responded to high gas prices by increasing auto occupancies. If car occupancies increased from 1.57 to just 1.60, then cars became 1.8% more energy efficient, not 0.1 percent less.
While the Energy Data Book combines light and heavy rail, the National Transit Database (which is the ultimate source of the transit data in the Energy book) indicates that heavy rail became 6.1 percent more energy efficient, while light rail became 5.2 percent less energy efficient in 2007. It isn’t clear from the data why commuter and light rail lost energy efficiency in 2007, except that some major systems, such as New Jersey Transit and the Massachusetts Bay Transportation Authority, reported larger increases in electricity consumption than ridership.
Why did light and commuter rail decline? The National Transit Data Base only reports energy data for transit lines that are directly operated by transit agencies, and most of the new commuter rail lines are contracted out to companies such as Veolia. So we only have commuter rail data for New York City, New Jersey Transit, Boston, Philadelphia, and Chicago.
The numbers show that New Jersey Transit increased its energy consumption by 70 percent in 2007, partly because it took over some commuter lines that it had previously contracted out. Passenger miles grew by only 8 percent, so New Jersey Transit’s energy efficiencies declined by 58 percent. This change swamped all of the other changes in commuter rail energy efficiencies.
In the case of light rail, no single culprit is responsible for declining energy efficiencies. The nation’s two largest light-rail carriers, Boston and Los Angeles, both reported declines in light-rail ridership. Minneapolis reported a huge increase in energy consumption with a negligible increase in ridership. Energy efficiencies also declined significantly in Baltimore, Cleveland, New Jersey, and San Francisco light-rail systems.
I am not sure why the energy book says transit buses lost energy efficiency in 2007, as the transit data base says bus energy efficiencies grew by 2.9 percent. Trolley bus energy efficiencies declined slightly, but they are such a small share of the total that they shouldn’t make a different. Paratransit bus energy efficiencies also declined, but they aren’t included in the Energy Data Book.
For the first time, the 28th edition of the Energy Data Book has charts showing the 2007 energy efficiencies of individual light-, heavy-, and commuter-rail lines (see physical pages 66 and 67). These are similar to charts on pages 10 and 11 of my analysis of rail energy efficiencies. The Energy Data Book charts, however, are misleading in one important way: they include a bar showing the average for “all light rail (or heavy rail or commuter rail) systems.” But this is the simple average of the various systems, not an average weighted by the actual ridership on each system.
The Energy Data Book reports that the average for light rail, for example, is 7,605 BTUs per passenger mile. In fact, the average BTUs per passenger mile of all light-rail lines in 2007 was only 3,642. Unlike the Federal Transit Administration, the Antiplanner also distinguishes, where possible, between light rail and streetcars. The streetcar lines in Memphis, Tampa, Kenosha, Galveston, Little Rock, and New Orleans consumed an average of nearly 10,700 BTUs per passenger mile.
It appears safe to say that the energy efficiencies of all forms of passenger travel except light rail, commuter rail, and paratransit increased in 2007. It remains to be seen what modes can sustain these improvements in the long run.




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