From polluting exhaust spewed from tailpipes to caved-in roadways due to extreme weather, transportation and climate change have an intimate and insidious relationship, the Transportation Research Board (TRB) has outlined in a new paper.
"It's particularly timely now because we're seeing so many weather phenomena, from heat records to wildfires and severe droughts," said Cynthia Burbank, vice president of the global infrastructure consulting firm Parsons Brinckerhoff and an author of the document.
Based on studies by TRB and the National Academy of Sciences, the paper released last week is designed to be a succinct resource for professionals in the field on how transportation contributes to and is affected by climate change.
"It's obvious now that the climate is changing, so it's a good time to get [the information] in front of transportation folks to help them understand the climate issue, what is transportation's role in it, and what can be done to both adapt to a changing climate and reduce the impact," she said.
Transportation is the second-largest source of greenhouse gas emissions in the United States, at nearly 30 percent of the total output. It's also an area ripe for improvement.
Later this summer, the Obama administration is on track to finalize a 54.5 mpg fleetwide fuel economy standard for 2025. That policy and support for research on alternative fuels will make substantial inroads in reducing transportation emissions, said Burbank.
But with little to no movement on climate change legislation in Congress, the responsibility to tackle transportation's contribution has fallen on state and local leaders. And action depends largely on whether the public and elected officials understand climate change and think it's a high-priority issue, said Burbank.
Steering around the politics
In red states where residents are generally less supportive of climate science, transportation departments are more hesitant to engage in mitigation activities, she said. Adaptation, however, is a more universal concern.
"They may be in states where the public is skeptical ... but they're seeing the impacts, too," said Burbank.
In recent years, U.S. transportation infrastructure has taken a beating from extreme weather. Record-level flooding in 2010 and last year washed out roadways in Tennessee, Rhode Island, Iowa and Wisconsin, for instance. And in Vermont, Tropical Storm Irene turned sections of Route 107 into gaping holes.
Intense weather also disrupts and delays mass transit and freight networks, leaving its mark in economic loss.
Floods, rain and high winds aren't the only concerns. Just outside Washington, D.C., three Metro cars derailed earlier this month near the West Hyattsville station when air temperatures spiked above 95 degrees Fahrenheit, causing a "heat kink" in which the tracks got so hot they buckled.
While nearly all state and local transportation departments are addressing infrastructure adaptation in some way, certain states, such as Washington, Oregon, California and Massachusetts, are also taking on climate mitigation.
Reducing the number of vehicle miles traveled (VMT) is the most effective way to lower emissions, and transportation pricing is the best way to reduce VMT, said Burbank.
"It seems clear to me that the biggest way we're going to get reduction in VMT is if we have the guts to do pricing," she said. "Whether it's congestion or carbon pricing that would raise the cost of fuels, or parking pricing, they give everyone an incentive to think about how much they're driving."
She added, "But, of course, it's politically controversial."