If You Want Accurate Traffic Projections, Don't Listen to DOTs

Analysis by the State Smart Transportation Initiative (SSTI) finds that the traffic projections used by state and local transportation agencies, which form the basis for spending priorities, are consistently higher than actual results.

1 minute read

December 18, 2013, 8:00 AM PST

By Jonathan Nettler @nettsj


"Forecasts and assumptions about ever-increasing traffic are often used to justify agency decisions to expand roads. But these assumptions are increasingly divorced from reality," reports Angie Schmitt. "In fact, state and regional agencies aren’t just wrong some of the time. State DOTs and metropolitan planning organizations are getting it wrong every year, over and over again, by significant margins, according to SSTI’s analysis."

Tuesday, December 17, 2013 in DC.Streetsblog

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 4, 2025 - Diana Ionescu

Metrorail train pulling into newly opened subterranean station in Washington, D.C. with crowd on platform taking photos.

Congressman Proposes Bill to Rename DC Metro “Trump Train”

The Make Autorail Great Again Act would withhold federal funding to the system until the Washington Metropolitan Area Transit Authority (WMATA), rebrands as the Washington Metropolitan Authority for Greater Access (WMAGA).

June 2, 2025 - The Hill

White and yellow DART light rail train in Dallas, Texas with brick building in background.

DARTSpace Platform Streamlines Dallas TOD Application Process

The Dallas transit agency hopes a shorter permitting timeline will boost transit-oriented development around rail stations.

May 28, 2025 - Mass Transit

Sun rising over downtown Los Angeles with tall palm trees visible in foreground. Image is bright orange-red indicating extreme heat.

LA County Creating Action Plan to Tackle Extreme Heat

Los Angeles County is creating a Heat Action Plan to help communities stay safe during extreme heat, with steps like adding more shade, improving buildings, and supporting the neighborhoods most at risk.

June 9 - Los Angeles County Chief Sustainability Office

Small silver car driving over wide soeed cushion on asphalt road.

Maryland Plans Quick-Build Complete Streets Projects

The state will use low-cost interventions to improve road safety in five Maryland counties.

June 9 - Fox Baltimore

Nighttime view of downtown Los Angeles through arches of new 6th Street Viaduct.

Downtown Los Angeles Gears Up for Growth

A new report highlights Downtown L.A.’s ongoing revival through major housing projects, adaptive reuse, hospitality growth, and preparations for global events in the years ahead.

June 9 - Los Angeles Downtown News

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.