State departments of transportation (DOTs) have access to a growing number of tools that may allow them to evaluate the impact of greenhouse gas (GHG) emissions. However, research is needed to understand how such tools can best be incorporated into transportation decision-making processes and what additional tools may be necessary. Existing tools for transportation GHG strategy analysis have not been developed with transportation programming and project prioritization in mind. The available tools are either designed for strategic level evaluation of policies or project-level evaluation using data more detailed than is typically available during planning and programming. Other common tools for transportation evaluation, including statewide and regional travel demand models and emission factor models such as Motor Vehicle Emission Simulator MOVES, are limited in their ability to evaluate GHG reduction strategies, and typically require substantial modification and/or combination with other tools and methods.

The objective of this research is to advance the practice of incorporating GHG emissions evaluation into transportation decision-making and performance management. This will be accomplished by identifying and building upon the state of practice at state DOTs for considering transportation-related GHG emissions during planning, project prioritization, and performance management. State DOTs have access to certain tools that allow for estimation and evaluation of transportation emissions, but additional tools and methods are needed to inform decision-making and align with state and federal GHG emission-reduction goals.