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

Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions: Volume 2
Cobenefits and Implications for Other Key Transportation Goals and
Objectives
Strategies to reduce carbon-intensive travel activity have a number of common cobenefits,
implications for DOT goals and objectives, and implications for infrastructure finance, as
described below. Some strategies also have unique cobenefits and impacts which are
described in their respective subsections. They can be evaluated against the five strategic
goals of the U.S. DOT (identified in the U.S. DOT’s Strategic Plan), as well as other key
objectives established for transportation by the Obama Administration:
• Safety – Most travel activity strategies reduce VMT. By doing so, they should reduce
the number of crashes and associated costs and human impacts. Alternative modes
typically carry much smaller crash risks per passenger-mile or vehicle-mile than
highway travel.
• Reduced Congestion/Increased Mobility – Strategies that improve the availability and
quality or reduce the cost of travel options, as well as those that provide information
about options, can provide increased mobility to travelers. In particular, these
strategies include improved urban and intercity transit services, nonmotorized
improvements, commute-focused travel options programs, and traveler information.
Mobility benefits are particularly acute for low-income people for whom an
automobile may be a financial hardship, as well as for children, seniors, and those with
disabilities that make driving impossible. Strategies that are implemented through
requirements or disincentives (such as price increases) represent a constraint on
mobility and will make some people worse off. Any strategy that reduces VMT during
peak periods should also reduce congestion; however, this does not necessarily imply
an increase in mobility, as some people may have been discouraged from traveling due
to a higher cost or other disincentive.
• Global Connectivity – Strategies implemented in a way that improves passenger
movement to and through airports, border crossings, and intermodal terminals (or
infrastructure in the vicinity of these facilities) should improve global connectivity by
enhancing connections between modes and across national borders.
• Environmental Stewardship – All of the travel activity strategies reduce GHG
emissions by reducing vehicle travel and its associated energy consumption, without
changing the mix or source of fuels used. As a result of burning less fuel and reducing
VMT, most of these strategies should also result in reductions in other air pollutants,
including ozone precursors (volatile organic compounds and oxides of nitrogen),
carbon monoxide, particulates, and air toxics. A reasonably close correspondence is
expected between reductions in air pollutant emissions, VMT, and GHG emissions.
Strategies that affect congestion and travel speeds, such as those that reduce peakperiod
travel, may provide additional benefits by reducing emissions associated with
congestion. Strategies that involve shifting travel to other modes will have more
complicated effects because the emissions characteristics of each mode will differ. For
example, the diesel engines commonly used in buses and rail locomotives may in some
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