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managers in planning and decision making. The compen- GHG emissions were a principal factor in decision mak-
dium will cover strategies to reduce emissions from opera- ing more often for strategies that reduce agencies' emissions
tions, maintenance, and construction. The compendium will than for strategies that reduce emissions from the transpor-
provide information on the scale of emissions reductions tation sector. GHG emissions were a principal factor most
possible and typical costs of strategies. It will include an frequently in decisions to use alternative fuels. GHG emis-
emissions profile of a transit agency, as well as case studies sions were a principal factor least frequently for strategies
of strategies implemented by agencies. that increase vehicle passenger loads. This result probably
reflects the central role that increasing passenger loads plays
in achieving traditional goals of transit agencies.
GREENHOUSE GAS EMISSIONS IN DECISION MAKING
GHG emissions were more likely to play even a small
Transit agencies may implement strategies that reduce GHG role in decision making for strategies that reduce agencies'
emissions for many other reasons than reducing GHG emis- emissions than for strategies that reduce emissions from the
sions. Many of the strategies discussed provide important transportation sector. Approximately half of agencies said
customer service benefits, compliance with existing envi- that GHG emissions were a factor or a principal factor in
ronmental regulations, and cost savings. Reducing GHG decisions to pursue strategies to expand service, increase
emissions should not be seen as the only or principal rea- vehicle passenger loads, mitigate congestion, and promote
son to undertake such strategies, but rather one of many co- compact development. Upwards of two-thirds of agencies
benefits. GHG emission reductions alone typically are not said that GHG emissions were a factor or a principal factor
sufficient to justify pursuing such strategies under current in pursuing alternative fuels or vehicles, vehicle operations
agency planning practices and constraints. In addition, some and maintenance strategies, construction and maintenance
strategies may provide no net benefit to GHG emissions, but strategies, and other energy-efficiency and renewable energy
may be important for other reasons. Buses that serve disad- strategies. Awareness of the GHG impacts of strategies was
vantaged neighborhoods may have low passenger loads and very high among agencies planning or implementing strate-
therefore emit more GHGs than they save, but they provide a gies. For every strategy type, nearly all agencies were at least
valuable social service nonetheless. aware of the potential impacts on GHG emissions.
In planning and implementing strategies, agencies con-
sidered GHG emissions benefits to different degrees. Figure EFFECTIVENESS OF TRANSIT STRATEGIES
14 compares the role that GHG emissions played in various
types of strategies. Strategies are grouped together depend- Transit strategies' effectiveness at reducing GHG emis-
ing on whether they primarily reduce emissions from the sions depends on the design of strategies and the context of
transportation sector as a whole or reduce emissions from regional transportation systems. Several recent studies have
transit agencies. quantified the potential impact of broad transit strategies on
FIGURE 14 GHG emissions in decision making (percent of agencies planning or
implementing each strategy type) [Source : ICF analysis (unpublished)].
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GHG emissions, and more studies are ongoing. These stud- Several national studies are investigating the potential
ies generally have found that transit strategies would reduce of various transportation strategies, including broad transit
transportation GHG emissions at both the state and national strategies, to reduce GHG emissions. Three studies will be
levels, and have highlighted some key factors in determining released in 2009:
strategies' net impact on GHG emissions.
· Moving Cooler, a forthcoming report from the Urban
Many states have undertaken their own research on strat- Land Institute, will investigate strategies that could be
egies to reduce transportation GHG emissions, including implemented to reduce GHG emissions from personal
transit strategies, as part of climate action plans. Plans from travel. Improvements in public transportation are one
a sample of five different states have estimated the potential category of strategies that the work will assess. The
of those polices to reduce GHG emissions at between 0.2 project does not address technology-based strategies
and 5.8 MMtCO2e per year in 2020 (47 ). For comparison, for vehicles and fuels. Individual measures and bun-
all transportation emissions from the state of Delaware total dles of strategies will be analyzed for their cost-effec-
5.4 MMtCO2e per year (8). Results vary by state depending tiveness in reducing GHG emissions.
on analysis techniques, the size of the state, existing urban · A study for TRB, Potential Energy Savings and
development and transportation patterns, and the aggres- Greenhouse Gas Reductions from Transportation, is
siveness of policies proposed. A 2008 study by the Uni- reviewing policies and strategies to affect behavior
versity of Minnesota found that comprehensive transit and and improve fuel economy for passenger and freight
smart growth policies will be essential to meeting Minne- vehicles across all modes.
sota's goal to reduce GHG emissions 15% below 2005 levels · A study for the U.S.DOT is being completed in coor-
by 2015. The study found that construction of an extensive dination with the EPA and the U.S. Global Change
LRT or BRT network in the Twin Cities region could reduce Research Program. The report will summarize trans-
statewide vehicle-miles traveled (VMT) by 2.2% in 2025. portation's impact on climate change and strategies
Improvements to the region's existing transit system could to reduce the impact. It examines the GHG reduction
reduce statewide VMT by 0.3% (48). effects of alternative transportation strategies, and the
potential fuel savings and reductions in air pollution
ICF International recently estimated the GHG impacts associated with these strategies.
of a package of bus transit improvements for Washington's
Climate Action Plan. The scenarios considered as part of the Generally transit plans, whether they are for individual
analysis included a doubling of transit ridership, an increase stations, corridors, or entire systems, will include a range
in vehicle load factors, and a shift toward the use of hybrid of the strategies described in this chapter. The GHG impact
buses. The analysis found that the benefits of reduced VMT of plans depends on the net effect of many elements. A bus
from increased transit ridership in Washington may be offset expansion plan might include elements to increase the provi-
by an increase in emissions from an expanded diesel bus sion of bus service, increase ridership, and switch to more
fleet. As shown in Figure 15, the net effect on GHG emis- fuel-efficient buses. Strategies must be evaluated concur-
sions depends on assumptions for improvements in bus pro- rently to determine their composite effects on transporta-
ductivity (load factors) and bus fuel economy (through the tion GHG emissions. For example, a BRT system can reduce
introduction of diesel hybrids). Expanding the transit fleet greenhouse gas emissions by--
without increasing load factors or using cleaner vehicle tech-
nologies would produce a net increase in GHG emissions. · Using newer, more fuel-efficient high-capacity buses;
Converting the bus fleet to 75% diesel hybrids would gener- · Drawing more riders out of their cars and onto faster,
ate a net decrease in emissions. Simultaneously increasing more convenient transit;
load factors would reduce emissions even further.
FIGURE 15 GHG impacts of transit expansion scenarios in Washington State, 2020.
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· Capturing operational efficiencies through dedicated Chapter five describes techniques to analyze the impact
lanes and signal timing, as well as centrally managed of transit on GHG emissions through mode shift, reduced
dispatching; and congestion, compact development, and reductions from
· Potentially switching to low carbon alternative fuels transit vehicles and agency operations.
(49).
