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

Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions: Volume 2
consolidation centers. Further improvements to aviation system efficiency require both
research as well as funding for deployment.
Finally, planning requirements and/or technical assistance can support some strategies.
For example, State and metropolitan transportation agencies could be required to assess
the GHG emission impacts of transportation plans or projects and to identify and
incorporate GHG reduction strategies in their transportation plans, including system
efficiency improvements. GHG reduction practices also could be required in construction
and maintenance activities. Ports and airports could be required to conduct GHG
inventories and/or develop reduction plans. The U.S. DOT could provide technical
assistance (e.g., inventory and assessment tools, best practices guidance), either to support
these requirements or as a stand-alone measure to encourage transportation agencies to
address GHG emissions. Planning and regulatory strategies are discussed in more detail
in Section 8.0.
Summary Evaluation
Table 4.2 summarizes the strategies discussed in this section and presents an assessment
of each strategy’s effectiveness, cost-effectiveness, and cobenefits, as well as a summary of
key Federal policy initiatives that would be needed to implement the strategy beyond
current levels. The factors presented in the table are rated according to the following
metrics:
• Effectiveness: Low = < 0.5 percent of transportation GHG emissions in 2030 (12 mmt
CO2e; Moderate = 0.5-2.5 percent (12-60 mmt CO2e); High = > 2.5 percent (60 mmt CO2e).
• Costs: Cost is measured as “net included cost” per metric ton (tonne) of CO2e reduced. A
positive number represents increased costs, while a negative number represents a net
savings. High Cost = > $200 per tonne CO2e reduced; Moderate Cost = $20-$200 CO2e
reduced; Low Cost = < $20/tonne CO2e reduced; Net Savings = < $0/tonne CO2e
reduced. Costs for system efficiency strategies are presented in two ways:
− Direct costs (implementation costs only) per tonne of CO2e reduced; and
− “Net included costs” (which includes both direct costs and any reported cost
savings, usually vehicle operating costs). A discussion of how costs are calculated
and presented in this report is presented in Appendix A.
• Cobenefits: Plus (+) = significant positive cobenefits; minus (–) = significant negative
cobenefits; plus/minus (+/-) = both significant positive and negative cobenefits; zero (0) =
modest or negligible cobenefits.
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