It’s Happening: Washington State Revises Traffic Forecasts to Reflect Reality

Washington State has revised traffic projections downward, to reflect changing patterns. Image: Washington State via Sightline
The Washington State Office of Fiscal Management has revised its traffic projections downward to reflect changing patterns. Graph Washington OFM via Sightline

The amount that the average American drives each year has been declining for nearly a decade, yet most transportation agencies are still making decisions based on the notion that a new era of ceaseless traffic growth is right around the corner.

The Wisconsin Department of Transportation, for example, has overestimated traffic on its roads by an average of 73 percent, according to a recent study. And Dallas-area planners recently produced traffic projections that predicted a much larger increase in driving than the state DOT was even predicting.

That’s why a new traffic forecast from the Washington State Office of Fiscal Management is so interesting: It actually acknowledges how travel habits are changing. Seattle-based environmental think tank Sightline spotted the above traffic projection in a new government report. In its most recent financial forecast, the agency has abandoned the assumption of never-ending traffic growth that it employed as recently as last year. Instead, the agency has responded to recent trends, even projecting that total traffic will start to decline within the next ten years.

Sightline’s Clark Williams-Derry says that’s huge:

By undermining both the rationale for new roads and the belief that we’ll be able to pay for them, a forecast of flat traffic should help inject a needed dose of reality into the state’s transportation debates.

Of course, there’s no telling whether this forecast will be right. As Yogi Berra allegedly said, predictions are hard, especially about the future. But if it turns out that this forecast underestimates traffic growth, budgeters won’t find it such an unpleasant surprise, since more traffic will bring more revenue from drivers.

Update: This post has been amended to reflect that the traffic forecast was published by the Washington State Office of Financial Management, not the Washington State DOT, as originally reported. According to the OFM report, however, the projections were produced by a division of the DOT.

  • J

    This is big news! Finally, DOTs are admitting what the data has been telling them for the past ten years: traffic is not increasing, it’s flattened out overall and decreasing per person. This will lead to more sensible investments in transportation

  • This is extraordinary good news. Perhaps we should make a Streetfilm just on this one event and why they made their projections mirror reality.

  • Gezellig
  • Joe Linton

    It made my day when I saw this chart!!! If only California’s and Los Angeles’ DOT predictions were this sensible. A guy can hope!

  • Coolebra

    Washington DOT seems to be ahead of the curve in a number of areas when compared to their peer agencies.

    Why?

    It might be really cool to do the Streetfilm Clarence suggests, incorporating interviews with DOTs of differing perspectives – a sort of compare and contrast using the same questions.

  • Mike B

    Sort of, except for the $3 billion tunnel we’re building that’ll make everything worse for everyone by WSDOT’s own projections. I suppose that’s more politicians than anything…

  • neroden

    Realism! Woo!

  • neroden

    Well, if it’s any consolation, that tunnel will probably never be finished, though the $3 billion will still be wasted. Is it any consolation? (Maybe not.)

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