Study: Spending infrastructure funds on highway expansion could increase emissions

The recently passed bipartisan infrastructure bill could increase carbon dioxide emissions from the transportation sector, according to research from the nonpartisan Georgetown Climate Institute.

The $1 trillion package has been touted as a major step forward in the decarbonization of transportation, and the research found that it could accomplish that if it prioritizes electrification and road maintenance. However, an approach that involves building new roadways and adding lanes to existing ones could create a phenomenon known as “induced demand”— in other words, the existence of those new roads would induce more people to drive on them, creating further emissions.

While the bill allocates just under $600 billion for “surface transportation” spending, its specific uses would largely be at the discretion of individual states. Georgetown researchers mapped out two possible scenarios based on this flexibility. In the higher-emission scenario, 27 percent of the surface transportation money goes to expanding highways compared to 23 percent for maintenance.

The alternate low-emissions scenario, meanwhile, spends 38 percent on maintenance and just 4 percent on highway expansion.

Either scenario could bend the existing baseline trajectory of emissions in either direction, according to the research. Under the high-emission scenario, emissions could increase from that baseline by up to 1.6 percent, whereas under the low-emission scenario they could fall up to 1.6 percent over the next five years. This is about the equivalent of 4.5 million passenger vehicles’ annual emissions.

“We are not predicting that either extreme of these bounding cases is likely, but they are certainly both possible,” the researchers wrote. “In the end, we expect that actual investment levels for most strategies will fall between these approaches, and will depend on the choices state, local, and federal policymakers make about how to spend these funds, given the discretion and flexibility that they are afforded under the law.

“Importantly, decision makers looking to achieve climate goals have the opportunity to steer decisions in the direction of the lower-emission scenario.”