Study: Without Fewer Cars, Cities Will be 'Overrun by Gridlock'

Local leaders must invest in public transit and other incentives to reduce the number of private vehicles and congestion in cities.

2 minute read

July 15, 2021, 12:00 PM PDT

By Diana Ionescu @aworkoffiction


Traffic

Sofiaworld / Shutterstock

"Understanding how cars affect cities and commute times is of vital importance, both for the sake of the climate—transportation is the biggest share of U.S. emissions and a growing chunk globally—and quality of life," writes Dharna Noor. A new study "modeled the time car trips take, factoring in the baseline length of the trip on empty streets, the time added by other drivers who create traffic, and the time added by the designation of some street lanes for exclusive use by pedestrians, buses, and bikes" to conclude that "we have to start getting cars off the road—and fast—if we want to avoid cities being overrun by gridlock."

The choice between driving and using other modes of transit, Noor writes, "creates an inherent paradox. If more people decide that driving is quicker, there will be more traffic, clogging streets and making trips longer. The longest trips across town, the authors found, were the ones taken when every single resident tries to reduce their commute times by driving, thus creating the most traffic." 

"The authors also discuss some ways to reduce the time it takes to get across a city and lower carbon pollution, including investing in more reliable and quick public transit, building more bike lanes and walking paths, and not separating residential areas from commerce. They also suggest reducing the number of traffic lanes in cities and building less parking to discourage people from driving or even owning a car in the first place, making city travel faster for everyone."

Despite some limitations in the analysis, "the model is instructive, showing the logical fallacy of attempting to reduce drive times by increasing the use of cars."

Friday, June 25, 2021 in Gizmodo

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

July 16, 2025 - Diana Ionescu

Green vintage Chicago streetcar from the 1940s parked at the Illinois Railroad Museum in 1988.

Chicago’s Ghost Rails

Just beneath the surface of the modern city lie the remnants of its expansive early 20th-century streetcar system.

July 13, 2025 - WTTV

Blue and silver Amtrak train with vibrant green and yellow foliage in background.

Amtrak Cutting Jobs, Funding to High-Speed Rail

The agency plans to cut 10 percent of its workforce and has confirmed it will not fund new high-speed rail projects.

July 14, 2025 - Smart Cities Dive

Worker in yellow safety vest and hard hat looks up at servers in data center.

Ohio Forces Data Centers to Prepay for Power

Utilities are calling on states to hold data center operators responsible for new energy demands to prevent leaving consumers on the hook for their bills.

July 18 - Inside Climate News

Former MARTA CEO Collie Greenwood standing in front of MARTA HQ with blurred MARTA sign visible in background.

MARTA CEO Steps Down Amid Citizenship Concerns

MARTA’s board announced Thursday that its chief, who is from Canada, is resigning due to questions about his immigration status.

July 18 - WABE

Rendering of proposed protected bikeway in Santa Clara, California.

Silicon Valley ‘Bike Superhighway’ Awarded $14M State Grant

A Caltrans grant brings the 10-mile Central Bikeway project connecting Santa Clara and East San Jose closer to fruition.

July 17 - San José Spotlight