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

Transportation's Role in Reducing U.S. Greenhouse Gas Emissions: Volume 1
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drivetrains. For example, hybrid-electric vehicles typically achieve fuel
economy on urban driving cycles that is close to or exceeds fuel economy on
highway cycles. System efficiency is still a valuable goal for other reasons,
however, including improving mobility, reducing congestion and delay, and
reducing shippers’ costs.
• Transit, nonmotorized improvements, land use, and pricing strategies are
most effective when applied in combination. For example, TCRP Report 128:
Effects of Transit-Oriented Development (TOD) on Housing, Parking, and Travel,
surveyed 17 housing projects that combined compact land use with transit
access and found that these projects averaged 44 percent fewer vehicle trips
per weekday than that estimated by the Institute for Transportation
Engineers (ITE) manual for a typical housing development. 104 The Moving
Cooler study also found that transit and nonmotorized improvements were
more effective in areas of higher population density. 105
It further might be
expected that strategies that encourage the use of alternative modes (such as
road pricing) would have a greater impact when applied in conditions when
better alternatives exist (as would be found with increased transit investment
and more compact land use patterns), although evidence on the interactive
effects among all of these factors in combination is limited.
• Research combined with pricing signals and or technology forcing
regulations can reinforce one another. Federal research investments may be
successful in developing new alternative fuels and fuel efficiency
technologies, but without a market, these new technologies will not be
introduced. For instance, the Partnership for a New Generation of Vehicles,
begun in 1993 as a partnership between the Federal government and Detroit
automakers, produced 60 to 80 mpg diesel hybrid prototypes, however, these
new vehicles were never put into production. This illustrates the need not
just for research but for incentives and long-term carbon price signals to spur
mass production of low-carbon vehicles. Similarly, markets may exist for
low-carbon vehicles but auto manufacturers may be reluctant to invest
heavily in technology development because of the large investments needed
and the high risks for product failures.
• Some pricing strategies may be redundant with each other, although higher
prices through multiple mechanisms would of course have greater GHG
reduction benefits, and some measures can be complementary. Among
104 G.B. Arrington and Robert Cervero. Transit Cooperative Research Program (TCRP Report
128: Effects of TOD on Housing, Parking and Travel. Transportation Research Board:
Washington, DC, 2008.
105 Cambridge Systematics, Inc. (2009). Moving Cooler: An Analysis of Transportation
Strategies for Reducing Greenhouse Gas Emissions. Urban Land Institute: Washington,
D.C.