June 10


Guest Post from Bryant Ficek, PE, PTOE

On Wednesday, May 21, I attended the Center for Transportation Research’s 25th Annual Research Conference. The opening session had a presentation titled “The End of Car Culture? Socio-Demographic Trends and Travel Demand” and follow-up panel discussion.

As the synopsis reads:

“In the next 30 to 40 years, the transportation industry will face many challenges caused by new and emerging trends. These trends—in areas ranging from technology to climate change to the economy—will dramatically reshape transportation priorities and needs. To help practitioners face these changes and effectively shape the future, a National Cooperative Highway Research Program study (20-83) is investigating these emerging trends and their implications for the transportation system.”

The speaker, John Njord, served as CEO of the Utah Department of Transportation for 12 years where he led a similar initiative to look at coming trends. I found this to be a great presentation for two reasons:

  1. The presentation itself was nicely done. In my opinion, presentations should use more pictures and less text. I came to hear you, not read tech memo. John did a great job of using pictures and a minimal amount of text to support his speech. He was the primary focus through-out, not the other way around. I try to do this in my own presentations, which forces me to think about my presentation more and ensures I know the material in-depth. It’s not always easy to effectively incorporate meaningful graphics, but your audience will definitely enjoy your presentation more than just a bunch of slides of text.
  2. CaptureProbably more importantly, John brings up a great point about planning for the future. The adjacent graphic, courtesy of the Center for Transportation Studies, shows four potential trends for the future: Momentum, Global Chaos, Tech Triumphs, and Gentle Footprint. If one trend becomes dominant, the resultant demand on the transportation network would look vastly different compared to the other trends.

John was talking about broad-based, long-term planning. However, I think these four trends also resonate with the future of traffic studies. For traffic impact studies, we start with a new land use, use ITE trip generation, distribute that traffic to the network, and determine appropriate mitigation. It is typically a straight-forward process that generates one answer – here’s what your future intersection, corridor, or network should be.

But what happens if our trip generation is off. If transit and bike use is very high, have we just recommended spending resources on unnecessary improvements, or worse forcing someone from their property to make room for a new road?

What if a business comes in with lots of commuters, lots of incoming deliveries, and lots of outgoing shipments? Did we end up not recommending enough improvements and have doomed the public to congestion for 6 to 10 hours a day?

I think that our basic traffic impact study could be improved by introducing some variables and examining a range of options. If we examine several scenarios and they end up requiring the same potential mitigation, it would strengthen our case for those improvements. If each scenario results in different mitigation, then we have tough, but important decisions to make based on which scenario we think will be closest to reality.

I’ll explore this topic and idea more in upcoming posts, but please check out John Njord’s presentation at http://www.cts.umn.edu/events/conference/2014/index.html. I think you’ll find it as thought-provoking as I did.

Mike’s Take – The idea of iterating capacity analyses around ranges of input variables is very interesting, per Bryant’s post.  I touched on this in my post about Nate Silver’s The Signal and the Noise.  Now that we have more powerful forecasting software programs, I think the time is right to shift how we do traffic impact studies.  Teaser – Bryant and I have plans to flesh this idea out over the next year. 

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Mike Spack

My mission is to help traffic engineers, transportation planners, and other transportation professionals improve our world.

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