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Transportation Greenhouse Gas Emissions Impact Assessment
In 2023, the Minnesota Legislature created new requirements to ensure transportation projects that expand highway system offset the impacts. Projects that expand the amount of lanes on the highway system or add new interchanges now need to conform with the state’s greenhouse gas emissions (GHG) reduction and vehicle miles traveled (VMT) reduction targets. The legislation requires projects to address the impacts by either modifying the scope or design, halt the project, or offset impacts.
The legislature identified nine categories that projects could use to offset the potential impacts. The categories involve a combination of policy incentives and infrastructure investments that allow local communities to plan offsets according to the local community context.
Why Minnesota is working to reduce emissions
The transportation sector is the largest source of carbon emissions in Minnesota, with surface transportation sources, such as cars, trucks and buses making up about 24% of carbon emissions in 2022. Transportation carbon emissions are primarily the result of fossil fuel combustion in vehicles and are most significantly influenced by:
- Fuel type and fuel efficiency of the vehicles used (such as conventional gasoline or diesel, biofuels or other alternative fuels) and
- The multimodal transportation options (such as transit or biking) people have to get to their destinations (such as homes, business, and schools)
Fuel type and vehicle efficiency matter and so does the mix of transportation options people have to get to their destinations. The rate of vehicle miles traveled decreases – and associated emissions - when there are transportation options and more connected development patterns.
Carbon emissions are also produced from transportation infrastructure construction and maintenance and the generation of electricity used in equipment, facilities and EVs, as well as other upstream emissions from fuel processing. These carbon emissions are not accounted for as transportation sector emissions but are important to consider when looking at the overall impact of transportation systems on statewide emissions.
MnDOT’s role in reducing emissions
To meet Minnesota’s climate targets, multiple strategies are needed to reduce carbon emissions in transportation beyond the transition to electric and zero emissions vehicles.
The legislature directed the transportation community to look more directly at the unintended emission impacts of capacity expansion of highways, the role of land use and figure out how to offset impacts.
Greenhouse gas (GHG) emission and per capita vehicle miles traveled (VMT) reduction support MnDOT’s mission to connect and serve all people through a safe, equitable and sustainable transportation system.
How impacts from capacity expansion will be assessed
A complete outline of the process is outline in the Emissions and VMT Impact Assessment and Offset Plan Procedure.
Step 1: Determine if a project meets the definition of a highway capacity expansion project
The requirement to complete an Impact Assessment and Offset Plan only applies to projects on the Minnesota Trunk Highway System that meet the definition of a highway capacity expansion project as defined by law. If the project meets the definition, then an Assessment is required, and Step 2 should be completed. For further clarification on if a project is considered a capacity expansion project refer to Defining lane expansions and new interchanges and contact staff.
Step 2: Select impact analysis method and determine project impacts to vehicle miles traveled (VMT)
There are two ways a Project Proposer can calculate the VMT impacts of a capacity expansion project: (A) using an Elasticity Calculation, or (B) using a Travel Demand Forecast Model, hereby referred to as a Model for the remainder of the document. This step provides instructions on how to analyze the impacts of VMT and document the process specific to a project.
Step 3: Determine an expansion project’s emissions impacts
Project Proposers will estimate a project’s impact on GHG emissions from the additional travel (e.g. VMT) that a project creates as was calculated in Step 2.
Step 4: Determine an expansion project’s emissions impacts
When VMT and GHG emissions impacts are identified, an Offset Plan must be developed and validated before a capacity expansion project enters the State Transportation Improvement Program of a Metropolitan Planning Organization’s Transportation Improvement Program.
Offsets categories
- Transit expansion [bus routes, Bus Rapid Transit, passenger rail]
- Transit service improvements [increase transit service level, transit fare reduction]
- Active transportation infrastructure [gap or standalone trail improvements, bike lane adds]
- Micromobility [shared vehicle services]
- Transportation demand management [vanpool and shared vehicle programs, telework programs, broadband access]
- Parking management [policies to reduce or eliminate parking requirements, increased parking costs]
- Land use changes [residential or other density increases, mixed-use development, transit-orientated development]
- Infrastructure improvements related to traffic operations [roundabouts, reduced-conflict intersections]
- Natural systems [prairie restoration, reforestation, wetland conservation, restorative agriculture practices]
- Land acquisition [easements, restoration and enhancement for outdoor recreation systems]
