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

Transportation's Role in Reducing U.S. Greenhouse Gas Emissions: Volume 1
Because of the global nature of climate change, GHG emissions impacts and
reduction strategies are more effectively evaluated and addressed at a regional or
systems level than at the transportation project level. A voluntary regional-level
analysis of transportation-related GHG emissions and reduction strategies
analysis may be appropriate at the planning stage. Some States already have
requirements to conduct GHG analysis for projects subject to State
environmental review requirements. Where such requirements are in place, or
where voluntary regional analyses are conducted, National Environmental
Policy Act (NEPA) documents could summarize information regarding regionallevel
analysis of transportation related GHG emissions and reduction strategies
from transportation plans and associated studies. The Council on Environmental
Quality is developing guidance on consideration of climate change in NEPA
documents. Any DOT guidance on NEPA would need to be consistent with
Council on Environmental Quality guidance.
Integrated Land Use and Scenario Planning
Better integrating transportation and land use planning is a major strategy
governments can undertake to improve access to housing, jobs, and other
destinations while reducing travel distances, and consequently GHG emissions.
Transportation and land use are interdependent. Decisions on the locations and
densities of housing, retail, offices, and commercial properties impact travel
patterns to these destinations. Similarly, the geographic placement of roads,
public transportation, airports, and rail lines influences where homes and
businesses are built. However, transportation planning and land use planning
often occur separately, frequently resulting in longer travel distances and higher
GHG emissions. By determining where and what type of transportation
infrastructure is built, and thus the travel options available, State and
metropolitan transportation planning greatly influences travel patterns, land use,
energy consumption, and, as a result, GHG emissions. Integrated transportation
and land use planning practices that promote clustered or higher density, mixed
use development, and colocation of services near transit can reduce emissions by
shortening driving distances. Similarly, infill, connected street networks, traffic
calming, sidewalks, bike lanes, and walking paths can provide alternatives to
carbon intensive travel.
Scenario planning or visioning efforts attempt to achieve a regional consensus on
desired future land use and transportation patterns, often focusing on longer
timeframe (30 to 50 years) than the standard 20-year transportation planning
horizon. MPOs and/or DOTs could be required to develop forecasts of GHGs
under different transportation and land use scenarios, and to undertake a
planning process with this broader focus. An example is California’s Senate Bill
(SB) 375, adopted in September 2008, which requires regional transportation
plans to include sustainable communities strategies as part of the plan to achieve
emission reduction targets. Federal policy would define clearly established
linkages between the long-range vision and the existing long-range
transportation plan.
4-7