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

Transportation's Role in Reducing U.S. Greenhouse Gas Emissions: Volume 1
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process. More importantly, many states and MPOs currently use planning
factors to define their State or regional transportation goals—general statements
of purpose that reflect a long-term desired end to a specific transportation need
or issue. A goal is typically very qualitative in nature, and is often only used to
communicate broader investment strategies to the public. However, when used
as part of a performance-based planning framework, goals are the key first step
in identifying potential solutions that address specific transportation needs, and
indicate a general direction for transportation investment. This becomes the
foundation for establishing performance measures which provide a mechanism
to “test” solutions and provide a quantitative means to describe the impact of a
project (or group of projects). Some States and MPOs are moving towards
performance-based planning (also an emphasis area in reauthorization) and
could use a GHG planning factor to support project and/or systems-level
evaluation of GHG reduction to demonstrate consideration of the factor.
More prescriptive actions would include a requirement to consider GHG
mitigation measures in plan development, or a requirement to develop GHG
inventories and forecasts for plan alternatives. This action would require DOTs
and MPOs to develop 1) a baseline inventory of existing GHG emissions from
transportation sources in their State or region, and 2) GHG forecasts associated
with each alternative evaluated in the long-range transportation plan. For some
MPOs the requirement could be relatively straightforward, as the MPO already
prepares baseline and plan alternative model runs using its regional travel
demand model, and a first-level GHG analysis could be added without much
effort. However, data and modeling improvements might be needed in many
metropolitan areas to develop better GHG estimates from strategies such as
traffic operations, transit, nonmotorized, land use design, and freight intermodal
improvements, which many of today’s models are not designed to analyze. The
requirements would have more significant implications for State DOTs, which
typically do not develop a full network model with a comprehensive set of
statewide projects to analyze plan alternatives. The inclusion of nonhighway
modes in the inventory requirement also would add another level of data
collection and analysis that does not currently exist at either level.
Such requirements would ensure that planning agencies consider the GHG
impacts of their actions. Inventory and forecast requirements would ensure that
information is introduced to inform decision-making. As with technical
assistance, however, these requirements would not guarantee that GHGreducing
strategies can be implemented. The acceptability of such requirements
to transportation planning agencies would likely decline in relationship to their
specificity. A statewide requirement to develop an inventory and forecast would
require the development of new technical capabilities and planning activities by
State DOTs. Resource requirements also would depend upon the type of
analysis required. A VMT-based inventory is relatively simple, but a more
detailed and precise inventory that captures factors such as vehicle operating
conditions is not supported by current tools.