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State and Local Climate and Energy Program


The transportation sector is a major source of greenhouse gas emissions (GHGs) in the United States. An estimated 29 percent of national GHGs are directly attributable to transportation–and in some regions the proportion is even higher. Transportation is also the fastest-growing source of GHGs in the U.S., accounting for 47 percent of the net increase in total U.S. emissions since 1990.

Transportation sources of GHG emissions include cars and light trucks, heavy trucks and buses, nonroad recreational vehicles (such as dirt bikes and snowmobiles), farm and construction machines, lawn and garden equipment, marine engines, aircraft, and locomotives.

Local Government Policy Options

There are many ways local governments can address GHGs from the transportation sector, but the three major options are through:

  • Fuels
  • Vehicles
  • Travel Activity (e.g., vehicle miles traveled, or VMT)

Transition to Lower GHG Fuels

Local governments can promote replacing gasoline and diesel with fuels such as biodiesel and natural gas, which can emit less GHGs.

Non-Government Fleets

The City of San Francisco, California, has developed a Clean Fleets Toolkit (PDF) (45 pp, 894K) of best management practices for commercial vehicle fleet managers.

Increased Use of Improved Vehicle Technologies

Local governments can promote the development and use of more fuel efficient vehicles, such as hybrid vehicles or plug-in hybrid electric vehicles (PHEVs), via policy decisions, tax credit programs, or “feebates” that can encourage the purchase of more fuel efficient vehicles.

Programs also can target government fleets (lead by example), residents (promote efficient vehicle purchases that score well in the Green Vehicle Guide), or commercial or corporate fleets (e.g., through the Smartway Partnership).

Reduce Growth of Vehicle Miles Traveled (VMT)

Implementing smartgrowth strategies that concentrate housing, employment, goods and services, and access to public transportation can lessen the need to drive. Offering transit options, providing pedestrian and bicycle facilities, and promoting travel demand management programs and telecommuting can also reduce the number of vehicle trips. Pricing mechanisms such as road pricing, mileage-based car insurance, and gas taxes can also motivate people to drive less.

Additional transportation control measures (TCMs)–strategies that reduce the demand for travel and increase the efficiency of travel that does occur–include:

  • Public transportation improvements
  • Incentives to encourage bicycling and walking
  • Expanded commuter choices
  • Workplace flexibility to reduce commuting
  • Idle reduction infrastructure, education, and requirements
  • Value pricing

Another effective way for local governments to address the transportation sector is to focus on government employee commuter practices. Public agencies can lead by example by adopting TCM programs for their own operations that they hope to see adopted by the private sector, such as telecommuting, flextime, compressed workweeks, staggered work hours, and incentives for public transportation and ridesharing.

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Federal Transportation Partnership Programs

Clean School Bus USA
Clean School Bus USA is a national partnership to minimize pollution from school buses. Leaders from corporate, children's health, environmental, and governmental organizations gather to design a plan to reduce children's exposure to diesel exhaust by eliminating unnecessary school bus idling, installing effective emission control systems on newer buses, and replacing the oldest buses in the fleet with newer ones. By reducing fuel use, some of these measures also have the added co-benefit of reducing GHGs.

It All Adds Up to Cleaner Air
It All Adds Up to Cleaner Air is a unique public education and partnership-building initiative developed collaboratively by several federal agencies to help regional, state, and community efforts to reduce traffic congestion and air pollution. It All Adds Up seeks to inform the public about the connection between their transportation choices, traffic congestion and air pollution, and emphasizes simple, convenient actions people can take to improve air quality and reduce congestion. This initiative helps state and local governments meet their mobility and clean air goals under two federal laws–the Transportation Equity Act for the 21st Century and the Clean Air Act Amendments. Many of the measures included in the program have the ancillary benefit of reducing GHGs.

National Clean Diesel Campaign (NCDC)
NCDC builds on the successes of EPA's regulatory and non-regulatory efforts to reduce emissions from diesel engines. The campaign works aggressively to reduce the pollution emitted from diesel engines through the implementation of varied innovative control strategies involving international, national, state, and local partners. Some of the efforts undertaken by partners–such as engine shutdowns and use of biodiesel–also result in GHG emission reductions.

SmartWay Transport Partnership
SmartWay is a collaborative program between EPA and the freight industry that will increase the energy efficiency and energy security of our country while significantly reducing air pollution and GHGs. The Partnership creates strong market-based incentives that challenge companies shipping products and the truck and rail companies delivering these products, to improve the environmental performance of their freight operations. SmartWay Transport partners improve their energy efficiency, save money, reduce GHG emissions and improve air quality.

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DOE Clean Cities program

The U.S. Department of Energy's (DOE) Clean Cities program strives to advance the nation's economic, environmental, and energy security by supporting local decisions to adopt practices that contribute to the reduction of petroleum consumption. Clean Cities has a network of approximately 90 volunteer coalitions, which develop public/private partnerships to promote alternative fuels and advanced vehicles, fuel blends, fuel economy, hybrid vehicles, and idle reduction.

EPA State and Local Transportation Resources

EPA provides topic-specific guidance documents that outline policies and methodologies for crediting programs (e.g., commuter programs, heavy duty retrofit, and fuels) that can help reduce transportation-related air pollution and emissions including:

  • Accelerated Retirement of Vehicles
  • Airports
  • Commuter Programs
  • Fuels
  • Idling
  • Intelligent Transportation Systems Management
  • Land Use
  • Retrofits
  • Transportation Control Measures
  • Transportation Pricing

Guidance on Air Pollution Control Strategies

EPA guidance documents outline basic processes in place for securing air quality credit for voluntary and innovative emission reduction programs in the context of state implementation plans, emission trading programs, and economic incentive programs. Most air pollution control strategies also reduce greenhouse gas emissions.

NREL Transportation Dashboard

The National Renewable Energy Laboratory's Transportation Dashboard includes transportation incentives and laws, a fuel economy guide, and information on alternative fuels.

Transportation and Climate Change Clearinghouse (TCCC)

The U.S. DOT's Transportation and Climate Change Clearinghouse provides information on climate change and transportation issues. It also offers resources and best practices information for state and local governments on integrating climate considerations into transportation decision making.

Transportation and Energy Data

The U.S. Department of Transportation has a publicly-accessible clearinghouse of transportation and energy data.

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Calculators and Modeling Tools

EPA provides several easy–to–use calculators and more sophisticated modeling tools to assess the effectiveness of mobile source–based control strategies. State and local agencies can use these calculators and tools to estimate emission reductions or to conduct an analysis of the outcome that a specific emission–reduction strategy may produce.

Diesel Emissions Quantifier

The Quantifier is an interactive tool that EPA has developed to help state/local governments, fleet owners/operators, school districts, municipalities, contractors, port authorities, and others to estimate emission reductions and cost effectiveness for clean diesel projects. Estimates are made using specific information about a fleet.


EPA's Office of Transportation and Air Quality (OTAQ) is developingthe MOtor Vehicle Emission Simulator (MOVES). This new emission modeling system will estimate emissions for on-road and nonroad mobile sources, cover a broad range of pollutants (including greenhouse gases) and allow multiple scale analysis--from fine-scale analysis to national inventory estimation.

NREL TransAtlas Tool

The NREL TransAtlas Tool is an interactive map that uses a Google Maps interface to display:

  • Existing and planned alternative fueling stations
  • Alternative fuel production facilities
  • Light–duty vehicle density
  • Roads and political boundaries

Transportation Analytical Tools

EPA tools and models are available to estimate emissions from on-road and nonroad mobile sources and the amount of greenhouse gas emissions that can be reduced through specific activities.

Transportation Emissions Guidebook

The Transportation Emissions Guidebook, Exit EPA disclaimer developed by the Center for Clean Air Policy (CCAP), aims to demonstrate to state and local officials the impact that policy decisions have on air pollution, greenhouse gas emissions, and energy use. It provides basic means of calculating these emission reductions from specific transportation and land use policies.

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