Acknowledgments US Department of Transportation - BTS

TABLE 4-20. Energy Intensity of Passenger ModesTABLE 4-21. Energy Intensity of Certificated Air Carriers, All ServicesTABLE 4-22. Energy Intensity of Passenger Cars, Other 2-Axle 4-Tire Vehicles, and MotorcyclesTABLE 4-24. Energy Intensity of Transit Motor BusesTABLE 4-25. Energy Intensity of Class I Railroad Freight ServiceTABLE 4-26. Energy Intensity of Amtrak ServiceTABLE 4-27. Energy Intensity of Amtrak Service (Loss-adjusted conversion factors)Total energy consumed for each mode can be estimated with reasonable accuracy. Miles traveled are known forsome modes, such as air carriers, but less accurately for others, most notably automobiles. When the numbers ofpassengers or tons are required to calculate energy efficiency, another uncertainty is introduced. Again, air carriersand intercity buses know how many passengers are on board and how far they travel, but only estimates areavailable for automobiles and intracity buses.Thus, table 4-21 should be quite accurate for certificated air carriers, though it is missing small airlines and privateaircraft. Table 4-22 is based on FHWA fuel tax data, derived from state fuel tax revenues. VMT is as discussed fortables 1-9 and 1-10.Data for motorcycles must be adjusted significantly more than for automobiles because lessinformation is collected from the states or from surveys. Transit bus data (table 4-24) are very uncertain because,unlike intercity buses, the distance each passenger travels is not measured by ticket sales.The intermodal comparison of passenger travel in table 4-20 must be viewed with considerable caution. Data for thedifferent modes are collected in different ways, and the preparation of the final results is based on differentassumptions. As noted above, airlines accurately record passenger miles, but the data on occupancy of privateautomobiles must be estimated from surveys. Even relatively certain data, such as state sales of gasoline, must bemodified to resolve anomalies, and transit data are even harder to make consistent. Furthermore, different groupscollect the data for the various modes, and they have different needs, assumptions, and methodologies. Thus, thecomparisons are only approximate.Freight service data (table 4-25) are from Railroad Facts, published annually by the Association of AmericanRailroads (AAR).AAR figures are based on 100 percent reporting by Class I railroads to the Surface TransportationBoard (STB) via Schedule 700 of the R1 Annual Report. STB defines Class I railroads as having operating revenuesat or above a threshold indexed to a base of $250 million (1991) and adjusted annually in concert with changes in theRailroad Freight Rate Index published by the Bureau of Labor Statistics. In 2000, the adjusted threshold for Class Irailroads was $ 261.9 million. Although Class I railroads comprise only 1 percent of the number of railroads in thecountry, they account for over 71 percent of the industry's mileage and 91 percent of all freight revenue; energy datashould be of the same order.TABLE 4-28. Annual Wasted Fuel Due to CongestionTABLE 4-29. Wasted Fuel per Eligible DriverThe Texas Transportation Institute's (TTI) Urban Roadway Congestion Annual Report provided figures for tables 4-27and 4-28. TTI relies on data from the U.S. Department of Transportation, Federal Highway Administration, HighwayPerformance Monitoring System database (HPMS). (See box 1-1 for detailed information about the HPMS.) TTIutilizes these data as inputs for its congestion estimation model. Detailed documentation for the TTI model andestimations can be found at http://mobility.tamu.edu/.The sum of fuel wasted in typical congestion (recurring delay) and incident related delays equal the annual wastedfuel for an urban area. Recurring delay is the product of recurring delay (annual hours in moderate, heavy, andsevere delays) and average peak period system speed divided by average fuel economy. Incident delay hours are