Transportation's Role in Reducing U.S. Greenhouse Gas Emissions ...

Transportations Role in Reducing U.S. Greenhouse Gas Emissions: Volume 2
that of conventional diesel (Clark et al., 2007). B20 also has slightly less stored energy
compared to conventional diesel fuel, meaning that operating range is slightly reduced for
a given tank size.
Other Transit Bus Technologies
Several other options comprise the balance of fuels used by transit authorities in the U.S.
For example, propane has gaining been popularity in some areas because it can be less
expensive per mile than diesel fuel, although capital costs related to converting buses to
run on propane can be upwards of $5,000 (McCann, 2008), and the overall supply of
propane is limited (since it is a byproduct of other petroleum product production) and its
price tends to closely track gasoline with the exception of some seasonal fluctuations (see
Section 2.5). Despite the recent interest in ethanol as a transportation fuel, it has not
penetrated the U.S. transit bus sector to date.
Various agencies and departments within the U.S. government are actively promoting the
development of advanced transit bus technologies. The FTA supports a grant program
that assists transit authorities as they seek to improve the environmental performance of
their fleets. DOE supports research and development into advanced transportation
technologies through its Advanced Technology Vehicles Manufacturing Loan and Clean
Cities programs. EPA manages several programs aimed to advance the development and
penetration of advanced transit technologies, such as the above mentioned National Clean
Diesel Campaign. Finally, the U.S. Department of Agriculture has been active in
providing guidance related to the use of biofuels in their Alternative Fuels and Fleet
Efficiency program (USDA, 2009).
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