Induced Demand Explained (or Why We Can't Build Our Way Out of Congestion)

In case you need an easy link to reference when encountering arguments in favor of widening roads and freeways as a solution for traffic, Adam Mann provides an accessible and clear explainer article that sums up the limitations of such strategies.

June 18, 2014, 12:00 PM PDT

By James Brasuell @CasualBrasuell


Los Angeles Traffic - The Newhall Pass

Jeff Turner (JefferyTurner) / Flickr

Adam Mann on why we can't build our way out of congestion: "The concept is called induced demand, which is economist-speak for when increasing the supply of something (like roads) makes people want that thing even more. Though some traffic engineers made note of this phenomenon at least as early as the 1960s, it is only in recent years that social scientists have collected enough data to show how this happens pretty much every time we build new roads." 

The article cites the research of Matthew Turner of the University of Toronto and Gilles Duranton of the University of Pennsylvania on the the fundamental law of road congestion, or, as Mann explains: "New roads will create new drivers, resulting in the intensity of traffic staying the same.

Mann explains how this counterintuitive reality can possibly be true: "As it turns out, we humans love moving around. And if you expand people’s ability to travel, they will do it more, living farther away from where they work and therefore being forced to drive into town. Making driving easier also means that people take more trips in the car than they otherwise would."

Mann also details two of what he considers to be more rational solutions for the problem, congestion pricing and the price of parking.

Tuesday, June 17, 2014 in Wired

A row of young people outdoors using smartphones

Say Goodbye to the ‘Millennial Lifestyle Subsidy’

The era of cheap, on-demand services is coming to a close as unprofitable startups face the realities of capitalism.

June 14, 2022 - The Atlantic

Minneapolis

Judge Blocks Minneapolis 2040 Implementation, Citing Lack of Environmental Review

Environmentalists have used the power of the legal system to protect the car-centric status quo of single-family zoning once again, overturning a landmark planning innovation in Minneapolis.

June 21, 2022 - MPR News

Unhoused person under a freeway overpass in Houston, Texas

How Houston Is Eliminating Chronic Homelessness

Taking a comprehensive ‘Housing First’ approach, the city of Houston has cut homelessness by 63 percent in the last decade.

June 15, 2022 - The New York Times

Tents lining an underpass in Los Angeles, California

Federal Funding To Boost Supportive Housing Efforts

The Department of Housing and Urban Development announced a $365 million package aimed at efforts to reduce homelessness and provide outreach and care for people lacking adequate housing.

June 24 - Bloomberg CityLab

Chicago Lake Michigan Trees

Protecting Chicago’s Tree Canopy

Advocates for urban greening are asking the city to boost its tree planting efforts and protect existing trees, which are a key tool for fighting the effects of climate change and worsening heat waves.

June 24 - Chicago Tribune

Close-up of curve ahead sign on highway

States Diverting Federal Road Safety Funds

Despite a nationwide rise in traffic fatalities, almost half of U.S. states have transferred federal road safety dollars to other projects.

June 24 - Route Fifty

Urban Design for Planners 1: Software Tools

This six-course series explores essential urban design concepts using open source software and equips planners with the tools they need to participate fully in the urban design process.

Hand Drawing Master Plans

This course aims to provide an introduction into Urban Design Sketching focused on how to hand draw master plans using a mix of colored markers.