Searching for Ways to Limit Induced Demand in a Car-centric Society - Governing

Reducing congestion and its problems of pollution and carbon emissions won’t be easy or cheap. But transportation experts continue to search for answers.

A high occupancy vehicle (HOV) lane near Seattle.(oksana.perkins/Shutterstock)
A high occupancy vehicle (HOV) lane near Seattle.(oksana.perkins/Shutterstock)

Editor’s note: This is the second in a two-part series about induced demand. Read the first article here.


American transportation planning is all about getting people to travel more and ensuring that experience is as frictionless as possible. Congestion mitigation is the name of the game.


For much of the post-World War II period that meant building roads, and not much else. In the wake of the 1956 Federal Aid Highway Act, the federal government began pouring $20 billion to $25 billion a year into expanding and maintaining the highway system. All that extra capacity, however, did not make driving a pleasure — especially during peak hours.


As the well-documented concept of “induced demand” or “induced travel” demonstrates, building more highways does not ease congestion. Instead it attracts more drivers, creating more deadly air pollution and more carbon emissions that contribute to climate change.


“For a long time, transportation policy’s goal was to get people to travel more, haul goods, go drive those interstates,” says Amy Lee, researcher at the University of California, Davis. “That was before we understood a lot of the air pollution and greenhouse gas externalities of driving. We're trying to think differently in an age of climate change, but it's a hard ship to turn around.”


In the last few decades, the concept of induced travel has become widely accepted in academic and planning circles. But its implications have not often been acted on. Partially that’s because of divisions within state departments of transportation, and because politicians are incentivized to endorse what seems like an easy answer: Surely traffic would ease if we widened this highway a little?


In recent years, transportation departments in California, Colorado and other states have incorporated the concept more thoroughly into their policy and planning. The U.S. Department of Transportation under Pete Buttigieg has acknowledged the concept, and in theory has more ability to influence state and local decisions due to the discretionary funds in 2021’s infrastructure law.


But in a society where mass car ownership has been the norm for at least three-quarters of a century, how do you solve a problem like traffic congestion?


Click here to read the full article.


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