Older Streets Are Safer Streets

Wes Marshall and Norman Garrick, after a study of data from 130,000 car crashes in California, have determined that cities built since since 1950 have more dangerous roads than those built before 1950.

1 minute read

January 30, 2009, 12:00 PM PST

By Tim Halbur


"The newer cities tend to have more "dendritic" networks - branching, tree-like organizations that include many cul-de-sacs, limiting the movement of traffic through residential areas. They also don't have as many intersections. The pre-1950 cities, on the other hand, tend to be more grid-like, giving motorists many more routes to choose from.

For several decades, traffic specialists believed a tree-like hierarchy of streets was superior because it made residential neighborhoods quieter and presumably safer. But an American Society of Civil Engineers (ASCE) study cited by the UConn researchers points out that more-connected street networks tend to reduce travel speeds. That's important because even a small reduction in speed can boost safety - mainly by reducing the severity of the accidents.

A recent report from Europe found that when average vehicle speeds drop by just 5 percent, the number of injuries drops by 10 percent and the number of fatalities falls 20 percent. Extensively connected street networks may not have fewer crashes over all, but the crashes that occur are less likely to leave someone dead."

Monday, January 26, 2009 in New Urban News

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

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, 2025 - Honolulu Civil Beat

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 2, 2025 - Diana Ionescu

Map of Haussmann's redesign of Paris in the 1850s through 1870s under Napoleon III.

In Urban Planning, AI Prompting Could be the New Design Thinking

Creativity has long been key to great urban design. What if we see AI as our new creative partner?

June 30, 2025 - Tom Sanchez

Street with parking protected bike lane and parked cars in downtown Portland, Oregon.

Portland Raises Parking Fees to Pay for Street Maintenance

The city is struggling to bridge a massive budget gap at the Bureau of Transportation, which largely depleted its reserves during the Civd-19 pandemic.

July 8 - Willamette Week

Aerial view of Spokane, Washington with river in foreground.

Spokane Mayor Introduces Housing Reforms Package

Mayor Lisa Brown’s proposals include deferring or waiving some development fees to encourage more affordable housing development.

July 8 - The Spokesman-Review

Close-up on black and white "Bike Lane Ends" sign with bike logo.

Houston Mayor Kills Another Bike Lane

The mayor rejected a proposed bike lane in the Montrose district in keeping with his pledge to maintain car lanes.

July 8 - Houston Public Media

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.

Associate/Senior Planner

Gallatin County Department of Planning & Community Development

Senior Planner

Heyer Gruel & Associates PA