Climate mitigation and the Highway System Plan

By James Detke

We seek to balance our policy goals of preservation, safety, stewardship, mobility, economic vitality, and environment when making decisions. Under limited funding this leads to difficult tradeoffs. The draft Highway System Plan (HSP) addresses many diverse and complex issues, one of which is Greenhouse Gas Emissions (GHG). To ensure the final funding recommendations balance policy goals and public preferences, the HSP includes GHG analysis of several investment scenarios.

Expanding infrastructure for people walking and biking on all roads including state highways can increase the number of people using low-emission transportation.

Modeling the outcomes of our options

We used state of the art analysis to test and compare the performance of different futures to inform decisions. This analysis examined how changes in funding would lead to changes in the transportation system and how people use it.

The final scenarios we considered provided between 2.3 and 3.7 percent reduction in greenhouse gas emissions when compared to the baseline scenario. The baseline uses estimated 2040 emissions with no changes to future funding.

The baseline is not the focus of the analysis but provides a common reference point to focus on the effects of the funding scenarios alone. A major feature of the baseline and all scenarios was consistency with the state energy strategy, which calls for all light duty vehicles sold from model year 2030 and beyond to be electric, including transit vans. Additionally, the analysis assumed there would be no changes to the powertrains or fuel sources of heavy trucks or transit buses. Our modeling excluded all marine vessels, vehicles and equipment off the roads, and aircraft.

Effective levers to reduce emissions

As part of our analysis, we created an illustrative scenario that examined the impact we could have when considering more than just highway program funding. The changes we examined in this analysis included tolling, fuel taxes, parking costs, congestion fees and more.

While we did not complete a full analysis due to time limitations, this unconstrained scenario provided a 12.19% reduction to GHG emissions compared to baseline. The meaningful reductions in emissions from changes to highway funding are just one part of the story. Changes in fuel sources and land use systems can lead to substantially greater reductions.

Along with our partners we are involved in larger projects that aim to reduce greenhouse gas emissions in our state through methods other than highway spending. The Washington State Energy Strategy outlines two main strategies to reduce emissions – one through efficiency improvements and the other through increasing adoption of electric and low-carbon fuel vehicles.

Moving people and goods more efficiently and equitably will require a combination of strategies that eliminate some trips, reduce the length of some trips, and improve transportation choices to substitute more efficient modes for driving alone. Vehicle travel can be reduced if we can access our jobs, education, goods, and services comfortably and efficiently using transit, walking, biking, rolling, or through online methods.

One big way we are working towards moving people efficiently is through complete streets. Complete streets is an approach to planning, designing, building, operating and maintaining the transportation system that enables safe and convenient access to destinations for all people using all types of transportation. All agency projects costing $500,000 or more are required to incorporate complete streets principles.

Totem Lake Freeway Station provides bus access for people walking, rolling and making transit connections. Active transportation and transit investments support transportation efficient land use strategies.

Another overarching method to limit transportation GHG emissions is to reduce the carbon intensity of transportation fuels. This means adopting electric vehicles (EV), promoting use of green hydrogen and low-carbon fuels, and reducing the embodied emissions in transportation infrastructure. Increasing EV and alternative-fuel use requires additional policies and programs to reduce the cost of these fuels and vehicles and improve the charging and refueling networks. The state is working on a variety of projects and programs to make electric vehicles more accessible to all our residents through incentives, charging network improvements, electrifying ferries, and other strategies.

An electric car being charged at a West Coast Electric Highway station in Skykomish. Transitioning to electric vehicles is an essential part of reducing emissions.

Incorporating public preferences

Public engagement was a vital part of creating the HSP. Understanding how people use the highway system and how they envision its future allows us to make recommendations that serve residents all over the state.

The public preferred scenario, which is our recommendation, strikes a balance between reducing greenhouse gas emissions, keeping our highway system in a state of good repair, and allowing strategic expansion that focuses on moving people and goods safely and efficiently. This scenario will result in a 2.3 percent reduction when compared to our baseline. Across the state we were fortunate to hear a diverse range of perspectives. Most people supported prioritizing repairing our highway system and funding safety and efficiency strategies while still providing some funding to expand the highway system.

Acting on climate change

We are working to reduce GHG emissions through collaborations, policy guidance, administering grants, and overall planning for a transportation system that has low carbon impacts. Find more information on our efforts to address transportation GHG emissions on our website.

Read and comment on the draft Highway System Plan

The draft Highway System Plan is available for public comment, and we want to hear from you! Your comments help us make recommendations that best serve the diverse communities affected by transportation decisions. Visit the HSP website to learn more, review the plan, and visit the online open house. There will also be a link to join the virtual public meeting from 2 to 3 p.m. on Nov. 30 where you can hear more about the plan and provide direct feedback.

Public comments will be accepted through 5 p.m., Dec. 18.