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

Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions: Volume 2
Figure 5.2 Annual GHG Emissions Reduction of Transit Expansion
GHG Reductions Compared to Baseline, mmt
35
30
25
20
15
10
5
Maximum
Aggressive
Expanded Best Practice
0
2010 2015 2020 2025 2030 2035 2040 2045
Source: Data from Cambridge Systematics, 2009.
Cost-Effectiveness
Expansion of transit infrastructure and service will require significant additional
investment. In a 2008 report to Congress, the National Surface Transportation Policy and
Revenue Study Commission estimated baseline transit investment needs based on the
“Improve Conditions and Performance” scenario (Commission, 2008). The analysis
estimated total transit baseline needs to be $1.1 trillion through 2020, $2.4 trillion through
2035, and $4.4 trillion through 2055, based on an annual transit travel growth rate of
1.57 percent. The average annual investment required through 2055 is $89.8 billion,
90 percent more than total funding from all sources in 2006. While some transit expansion
initiatives have been funded through local sources, in most areas, significant expansion
beyond current levels could require significant additional Federal investment—whether
for capital or operating expenses. The amount of additional local revenues leveraged by
this additional Federal investment will depend upon Federal match requirements, as well
as the ability of local sources to support the match requirements.
The AASHTO Bottom Line report (AASHTO, 2009) includes annual capital cost estimates
to accommodate new riders for each ridership scenario across four investment strategies
(Table 5.5). The investment strategy for maintaining physical conditions and improving
system performance assumes that the public transportation fleet and other assets will
continue to be replaced following current replacement cycles, and that additional
improvements are made to reduce passenger densities on the most crowded systems and
to improve overall speed of service.
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