Report: Narrow Traffic Lanes Improve Safety

Narrowing lanes can improve road safety and reclaim space for other uses.

1 minute read

November 13, 2023, 8:00 AM PST

By Diana Ionescu @aworkoffiction


New York City street with painted bike lane and crosswalk flanked by brick buildings.

Nick Starichenko / Adobe Stock

A new report from the Johns Hopkins School of Public Health concludes that narrower traffic lanes improve road safety. According to the report, “One major finding is that roads with 10–12-foot lanes at 30-35 mph speed limits have a significantly higher number of crashes compared to those with 9-foot lanes. Narrowing lane widths at these speeds provides city leaders with an opportunity to improve safety for all roadway users.”

Other key findings show that lane width affected safety on roads with speeds over 30 miles per hour and that narrower lanes “accommodate more users in less space, use less asphalt pavement, with less land consumption and smaller impervious surface areas.”

According to the report, “We found that the best candidates for lane width reduction projects are streets with 11–13-foot lanes in urban areas with speeds of 20-35 mph, as long as they are not used for heavy freight or transit.” The report recommends setting context-appropriate speed limits, factoring in pedestrians and other road users in planning decisions, setting a narrower lane standard, and using the extra space from lane narrowing for bike lanes or sidewalks.

Thursday, November 9, 2023 in Johns Hopkins Bloomberg School of Public Health

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

Use Code 25for25 at checkout for 25% off an annual plan!

Redlining map of Oakland and Berkeley.

Rethinking Redlining

For decades we have blamed 100-year-old maps for the patterns of spatial racial inequity that persist in American cities today. An esteemed researcher says: we’ve got it all wrong.

May 15, 2025 - Alan Mallach

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.

May 21, 2025 - Diana Ionescu

Rendering of California High-Speed Rail station with bullet train.

California High-Speed Rail's Plan to Right Itself

The railroad's new CEO thinks he can get the project back on track. The stars will need to align this summer.

May 19, 2025 - Benjamin Schneider

Red SF Muni ticketing machine.

San Francisco Muni Raises Fares a Second Time

A 10–cent fare hike for adults is part of the agency’s plan to chip away at a growing budget deficit.

May 21 - San Francisco Examiner

Electric car charging station with several Chevy Bolts charging in parking lot of store in Bellingham, Washington

Electric Grid Capacity Could Hamstring EV Growth

Industry leaders say the U.S. electric grid is unprepared for the increased demand for power created by electric cars, data centers, and electric homes.

May 21 - GovTech

Top view new development riverside residential and commercial neighborhood with vacant land in Texas, USA.

Texas Bill Supports Adaptive Reuse in Commercial Areas

Senate Bill 840, which was preliminarily approved by the state House, would allow residential construction in areas previously zoned for offices and commercial uses.

May 21 - The Texas Tribune