New Year’s Resolution: Honest Traffic Forecasts

Via Sightline:

No, that’s not my resolution, it’s one I’m proposing for Federal and State DOTs.

The State Smart Transportation Initiative has looked at 61 years of traffic forecasts and found that in all 61 cases, actual VMT was less than the forecast. This graph makes the case for reforming the forecasting process in the starkest terms possible:

VMT-C-P-chart-big1-541x550

Locally, we know that ODOT has done the same with projections for the Columbia River Crossing, sticking to a curve with a slope that’s been been demonstrated to be wrong each year since the projection was made (even before the projection was included in the EIS for the project).

So how about it, DOTs? For 2014 can we all resolve to acknowledge reality in our forecasting?

8 Comments

8 Responses to New Year’s Resolution: Honest Traffic Forecasts

  1. Ed
    January 2, 2014 at 1:42 pm Link

    This is a good wish. To be fair, transit agencies like TriMet could also do a better job with ridership projections. They historically predict more riders for things like light rail and BRT than what real takes place. Better projections all the way around!

  2. Lenny Anderson
    January 2, 2014 at 5:26 pm Link

    An interesting question for some of the data-geeks on this site, but I think MAX and Streetcar have delivered the promised number of riders or at least come close; haven’t seen the latest numbers but it must be now over 120K per day on rail or better than 1/3 of all transit riders. And at a considerable lower cost per ride for more reliable service. The DOTs, freight lobby, and various others keep trying to sell us more roads with wildly excessive projections…a bit like WOOPs’ energy projections in the 80’s. We all know where that got us. Default. Public investments in reliable transit have been and continute to be transformative and worth every penny.

    • Wells
      January 3, 2014 at 5:53 pm Link

      A question for the data-geeks here: MAX and Streetcar have delivered predicted ridership, must be over 120K daily, more than 1/3 all transit riders, at lower cost per ride 4 more reliable service. The DOTs, freight lobby, and others trying to sell us on more roads, wild projections, like WPPSS’ in the 80?s.
      Where that got us was “NO NEED FOR NUKULAR POWER”.
      A grateful nation THANKS President Carter for his outstanding “Home Weatherization Tax Credit Program”
      that preserved historic homestead structures circa 1880’s thru 1910s. Public investments in transit continute to be transformative and worth every penny. (Note: my 2-cents worth: Wsdot is the problem. Odot is Damngood
      HIGHWAY DEPARTMENT OF EXPERTS
      NOT SCREWING UP BADLY.
      O-D-O-T Rules, Baby!

    • Ed
      January 6, 2014 at 2:59 pm Link

      Here is the best I could find in terms of projections vs actual for TriMet’s light rail lines.

      http://www.nobridgetolls.com/documants/TriMet_Projections_vs_Actual3.PDF

    • Dave
      January 8, 2014 at 11:41 am Link

      If a road gets built and it’s at capacity within a few years, wouldn’t that be considered success? I mean you open a business and it’s overwhelmed with customers, most would consider that successful. Why not for a newly build roadway?

  3. Dwaine Dibbly
    January 2, 2014 at 6:54 pm Link

    I am shocked, I say shocked!, that the Oregonian hasn’t picked up on this story!

  4. Lenny Anderson
    January 7, 2014 at 5:35 pm Link

    Over time MAX has measured up…in November 2013 115k rides per day (Streetcar is another 15K), well over 1/3 of TriMet’s 314K riders. People ride it!

  5. EngineerScotty
    January 8, 2014 at 2:00 pm Link

    Generally, the ridership projections that matter are the ones that are published around the FFGA or FEIS stage. Those are the numbers that typically drive decisions around funding or construction (or should), not any preliminary numbers.

    MAX has generally done pretty well against those numbers. And even 80% of target, particularly if a recession (and service cuts that reduce available seats and make the service less attractive) intervenes, is not an outrage. (It’s the projects where ridership is well less than half of projections that ought to raise red flags).

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