Traffic Safety Silver Bullet: Prohibit the 12-Foot Traffic Lane

Jeff Speck, author of Walkable City, argues that reducing the width of traffic lanes would be a panacea for the disastrous public health outcomes of traffic safety.

1 minute read

October 6, 2014, 2:00 PM PDT

By James Brasuell @CasualBrasuell


Orlando Street

Nataliya Hora / Shutterstock

Jeff Speck makes a strong statement in an article for CityLab: "the single best thing we can do for the health, wealth, and integrity of this great nation is to forbid the construction, ever again, of any traffic lane wider than 10 feet."

The article begins by setting the history of the 12-foot lane and the agencies that have designed wide lanes despite the consequences. Many cities design streets with lanes wider than ten feet, according to Speck, and "states and counties almost always apply a 12-foot standard."

Speck goes on to address the consequences of that choice: "Why do they do this? Because they believe that wider lanes are safer. And in this belief, they are dead wrong. Or, to be more accurate, they are wrong, and thousands of Americans are dead."

Speck goes on to detail the errors in understanding and judgment that allow for 12-foot lanes as well as "evidence compiled by traffic engineers, for traffic engineers" against 12-foot lanes. 

Monday, October 6, 2014 in CityLab

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.

June 25, 2025 - Diana Ionescu

Person wearing mask walking through temporary outdoor dining setup lined with bistro lights at dusk in New York City.

Restaurant Patios Were a Pandemic Win — Why Were They so Hard to Keep?

Social distancing requirements and changes in travel patterns prompted cities to pilot new uses for street and sidewalk space. Then it got complicated.

June 19, 2025 - Diana Ionescu

Map of Western U.S. indicating public lands that would be for sale under a Senate plan in yellow and green.

Map: Where Senate Republicans Want to Sell Your Public Lands

For public land advocates, the Senate Republicans’ proposal to sell millions of acres of public land in the West is “the biggest fight of their careers.”

June 19, 2025 - Outdoor Life

Aerial view of town of Wailuku in Maui, Hawaii with mountains in background against cloudy sunset sky.

Maui's Vacation Rental Debate Turns Ugly

Verbal attacks, misinformation campaigns and fistfights plague a high-stakes debate to convert thousands of vacation rentals into long-term housing.

July 1 - Honolulu Civil Beat

White and purple sign for Slow Street in San Francisco, California with people crossing crosswalk.

San Francisco Suspends Traffic Calming Amidst Record Deaths

Citing “a challenging fiscal landscape,” the city will cease the program on the heels of 42 traffic deaths, including 24 pedestrians.

July 1 - KQED

Tents inhabited by unhoused people lined up on sidewalk in Los Angeles, California in front of industrial building.

California Homeless Arrests, Citations Spike After Ruling

An investigation reveals that anti-homeless actions increased up to 500% after Grants Pass v. Johnson — even in cities claiming no policy change.

July 1 - Times of San Diego

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.

Planning for Universal Design

Learn the tools for implementing Universal Design in planning regulations.