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

Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions: Volume 2
Table 4.1 Combined System Efficiency Strategy Benefits (2030)
GHG Reduction from
Percent of All
Baseline, mmt CO2e Transportation Emissions
Year Low High Low High
Highway and Truck Strategies 44 78 2.0% 3.6%
Air, Rail, and Marine Strategies 12 37 0.6% 1.7%
All Strategies 63 131 2.9% 6.1%
Policy Implications
The level of implementation of some of these strategies is constrained by funding.
Highway improvements, in particular, are traditionally funded through the Federal-aid
process as well as by State and local governments. Broader deployment of traffic
management and information has few barriers aside from funding availability; these
strategies can generally be implemented at modest cost compared to traditional capacity
expansion strategies, and these improvements are generally not controversial. Bottleneck
relief projects also can be accelerated through funding but are more likely to raise
community or environmental concerns in some locations. Federal funding also could
accelerate aviation avionics equipage and rail infrastructure improvements beyond
current levels of private sector investment; this would require a significantly greater level
of Federal involvement compared to current practice. Funding for system efficiency
initiatives could be provided through existing or new programs in the form of broad
support for the general types of projects that reduce GHG, or awarded on a performance
basis for specific projects that meet demonstrated levels of GHG reduction costeffectiveness.
Other strategies may require regulatory changes for implementation. Speed limit
reductions could be implemented through a uniform national speed limit, combined with
requirements or incentives for strict enforcement by States. Federal implementation of a
uniform anti-idling law, combined with incentives to defray up-front costs for vehicle
owners, would encourage adoption of this technology for trucks. Requirements or
voluntary agreements also could be developed with railroads and port operators to
implement idling reduction and other GHG reduction practices in rail yards, ports, and
intermodal terminals.
Research and development activities could advance other strategies that rely on yet
unproven technologies. Examples of efficiency strategies that require further R&D
include advancement of warm-mix asphalt and demonstration of the viability of urban
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