Shifting Gears: Policies for a More Sustainable Highway System

The Environmental and Energy Study Institute (EESI) held a briefing focused on the past, present, and future of the U.S. highway system. Since the end of World War II, Congress has paved the way for thousands of miles of roadways to connect U.S. towns and cities and foster economic activity. But highways have divided us as much as they have connected us. Multilane roads have bisected communities, made it hard to get around without personal vehicles, and even prevented wildlife from moving within habitats. Highways have also come with an ever-increasing price tag, with $62 billion allocated to the Federal Highway Administration for maintenance, repair, and expansion in fiscal year 2025.

This briefing highlighted how the country’s highways can be maintained in the context of a changing climate, from increasing preparedness for extreme weather events to building out electric vehicle charging corridors. Panelists highlighted opportunities for federal policy to help relocate highways to reconnect communities, use cool pavement and climate-smart building materials, and manage toxic runoff from roads. The briefing also identified opportunities to optimize federal funding to improve the way the country’s highways connect people.

This briefing was part of a series focused on the role of federal transportation and infrastructure investments in strengthening communities, increasing economic opportunity, building resilience, and reducing greenhouse gas emissions in the lead up to the next surface transportation reauthorization bill. View the full briefing series at eesi.org/transit-briefings.

Highlights

KEY TAKEAWAYS

State and local governments and organizations are exploring ways to make highways more multimodal, invest in electric vehicle (EV) infrastructure, and safeguard ecosystems from stormwater runoff.  Community perspectives improve the outcomes of highway projects that run through cities, leading to safer streets and a higher quality of life for people living along highway corridors.  In 2023, 1.1 million new vehicles purchased in the United States (about 8% of the total) were electric. Studies predict that EV adoption will continue to increase with or without federal rebates or incentives.  Green stormwater infrastructure along highways, which is funded by the National Estuary Program among other federal programs, can remove toxic chemicals from stormwater.

 

MJ Carpio, Executive Director, Move Minnesota

• Minnesota saw critical developments in state-level funding for sustainable and inclusive public transportation in 2023 and 2024.
• The Regional Transportation Sales and Use Tax is a new 0.75% sales tax for the Twin Cities area that generates about $440 million annually. The funding is used to electrify bus fleets, reduce fares, and improve service frequency to suburban areas.
• The Transportation Greenhouse Gas Emissions Impact Assessment law in Minnesota is designed to curb highway expansion and link transportation initiatives to the state’s climate goals.
• The Minnesota Department of Transportation must now assess the impact of new highway projects on vehicle miles traveled and greenhouse gas emissions and make sure projects reduce both.
• Move Minnesota participates in a working group to examine how particular projects would impact vehicle miles traveled.
• If a project does not decrease vehicle miles traveled and emissions, then the project implementer must take mitigation measures like paying for public transportation improvements.
• The Minnesota Department of Transportation can now collect greenhouse gas emission and vehicle miles traveled data from cities and counties across the state. This will allow the state to expand the law to all roads, not just highways, in the future.
• Move Minnesota is also working with the state to redefine “highway purposes” to be inclusive of transit, biking, and walking. They are also encouraging a rethinking of what highway funding can support.

 

Dave Gula, Principal Planner, Wilmington Area Planning Council (WILMAPCO)

• From 2021-2023, the Delaware Department of Transportation carried out a significant I-95 rehabilitation project through Wilmington. Building upon input during that rehabilitation project, the state wanted to work with communities to address some of their concerns and looked to the Wilmington Area Planning Council (WILMAPCO) to coordinate with community members.
• WILMAPCO gathered an advisory committee and held workshops virtually and in-person at churches and schools to gather input.
• People living along the I-95 corridor suggested that safety and quality of life would be improved by better sound barriers, adequate lighting, protected walkways, and green space. The community also emphasized the importance of an entity having responsibility for the space and a commitment to long-term maintenance.
• One option is to put a cap (or cover) over I-95, to build a park that reconnects communities over the interstate.
• A highway cap is multiuse. The Wilmington community considered options for bike infrastructure, pollinator gardens, playgrounds, dog parks, public art, gathering spaces, a cafe, and community gardens.
• The first phase of the I-95 cap project is estimated to cost about $100 million.
• The community has ownership over the cap project, given their involvement throughout the planning phase. Significant grant funding will be needed to bring the project plan to reality.

 

Robert Mowat, Zero Emissions Mobility Practice Lead, HDR Inc.

• Electric vehicle (EV) technology and adoption have evolved significantly from 2010 to 2025. EVs went from a proof of concept adopted by environmentally-conscious consumers to a high-end vehicle option to mainstream vehicles as battery costs and charging times have decreased and vehicle range has increased.
• In 2023, 1.1 million new vehicles purchased in the United States (about 8% of the total) were electric. Studies predict that EV adoption will continue to increase with or without federal rebates or incentives.
• About 80% of EV charging takes place at home and 20% of charging happens along the road or at destinations.
• The National Renewable Energy Laboratory estimates that one million more public chargers will need to be installed by 2030. That would mean installing an average of 438 public ports per day.
• While much discourse around EVs centers on vehicles and chargers, in reality, there is a much larger ecosystem of design, software, manufacturing, service, and support that holds up this new industry.
• The global electric vehicle and battery market is moving, and it will continue to grow.
• The United States has a history of strong investment in transportation technology. This public investment sparks private investment.
• The Infrastructure Investment and Jobs Act of 2021 (IIJA) (P.L. 117-58) created two federal programs to promote EV charging infrastructure buildout:
  • The National Electric Vehicle Infrastructure (NEVI) Program is a formula-based grant program that aims to build a charging spine along corridors that will allow people to move between cities and states easily.
  • The Charging and Fueling Infrastructure (CFI) Program is a discretionary grant program to support community-based charging.
• Freight presents a significant challenge for electrification, but one that is worthy of attention. RMI found that 60% of medium-duty and 43% of heavy-duty trucking could be done with today’s vehicle electrification technology. The return on investment can be significant for freight companies.
• Investments in EVs and charging, as well as in the wider EV ecosystem, provide more choice to individuals and companies.

 

Chelsea Mitchell, Senior Ecotoxicologist, King County, Washington State

• Over three trillion vehicle miles are driven on U.S. highways every year. When it rains, thousands of chemicals released from vehicles are carried into local ecosystems by stormwater runoff.
• In Washington State’s Puget Sound region, stormwater is the number one factor degrading water quality.
• Tire wear, which occurs as cars drive on the road and generate friction, releases chemicals into the environment.
• One toxic chemical resulting from tire wear that is found in stormwater is 6PPD-quinone. Scientists in the Puget Sound region have identified that it is killing fish quickly even when it appears in the water at low levels.
• 6PPD-quinone is responsible for massive coho salmon die-offs in Washington State and other fish population die-offs across the United States.
• Green stormwater infrastructure next to roadways can capture stormwater and filter it, removing pollutants.
• Bioretention mixes, which are engineered soils used to treat water; bioretention facilities; and porous asphalt overlays are strategies being adopted in Washington to remove 6PPD-quinone from water. Scientists are finding that these methods work in the lab and in the field.
• Federal funding from the IIJA and the National Estuary Program is critical to research solutions to mitigate the impacts of 6PPD-quinone and other toxic chemicals in stormwater.

 

Q&A

 

Q: How much does state and local work interface with federal funding and programs when it comes to highways? Could you share an example of a partnership with the federal government and how that has advanced your work?

Carpio

• The federal government provides Minnesota and other states with highway funding. This federal funding is flexible, and states can redirect it to climate-positive, multimodal investments, if they choose.
• Move Minnesota and the regional transit system in the Twin Cities also receive money from the Congestion Mitigation and Air Quality Improvement Program.

Gula

• As the metropolitan planning organization for the Wilmington area, WILMAPCO works closely with the Delaware Department of Transportation to align work and funding.
• A walkway set to be constructed over I-95 to connect two trail networks is an example of collaboration between state and federal authorities.

Mowat

• Federal dollars are being used exclusively or as a match to local funding and state efforts.
• Private investment is leading the way in a lot of areas. However, in areas where the private sector sees little demand and investors have not shown up, federal funding is required to build out EV charging networks.

Mitchell

• The National Estuary Program helps with water pollution research and stormwater management infrastructure.
• State and local governments often cannot fund significant capital projects on their own. The IIJA has filled in the funding gaps to make it possible to carry out larger scale efforts to treat stormwater and provide green space.

 

Compiled by Erin Parker and Jasmine Wynn and edited for clarity and length. This is not a transcript.