“The Barrier”: How Specific Do I Need to be About the Transportation Model?


In my initial version of “The Barrier” I was kind of skimpy on the details of the issues with the transportation model. With the rewrite, I felt I needed to make that more detailed.

I revised 4 more scenes this week. I’ve done 14 of the 39 scenes I plan to rewrite. Most of the remaining scenes have only minor changes, but there are four scenes that need major rewrites. In those scenes I had the characters talk in vague generalities about the issues that come up about the transportation model. I started to work on those specifics this week.

I’ve run into some barriers of my own.

Hazy Memory

It’s been 13 years since I last worked in transportation forecasting, and 7 years since I actively kept up with developments in the field. My memory has faded somewhat over those years. Transportation models have thousands of details that can become controversial. I struggled to remember a handful of major issues. I’m sure that as I think about it more, some more will come to mind.

Dated Knowledge

Since I haven’t kept up on new developments, the criticisms of transportation models may well have changed. Around the time I left the field, new types of models were being introduced that were supposed to address some of the major criticisms of existing transportation models.

It may well be that some of the issues I want to use in the movie are no longer relevant. No doubt there would be some criticism of  the newer models, but I wouldn’t know what they would be. I’m not keen to do a lot of research to update my self. Maybe someone can give me some suggestions I can use.

I do remember one criticism of the newer models was how much more time and effort they took to run. That isn’t an issue I can use in my movie. Another was the perennial complaint about models that they were black boxes that nobody understood. I already use this in the movie. I even call the model software “BlackBox by VooDoo”.

What I don’t believe has changed is that forecasting models are still the weak link in the planning process. Knowledgeable people who want to question transportation plans will go after the forecasts. You can see the same pattern in the climate change debate.

Avoid Confusion

I worry that if I get too specific about the transportation model, people without some background in the field will get confused. On the other hand, the vague descriptions I used in the last version of “The Barrier” confused people anyway. I need to strike a balance where most viewers can follow what is happening.

The issues with the model are what Alfred Hitchcock used to call a McGuffin. It’s what the characters in the movie think is important, but it isn’t important to the story or the audience.


My first inclination is to use the jargon that transportation planners would use. The problem with that approach is that then I would have to explain what the term means. I’ve done that in a few places already. I had the developer play dumb to force the engineers to explain what they meant.

In the scenes I need to revise, the characters should know what they talking about, which eliminates any excuse for characters to explain. The approach I have in mind is to have the characters describe the real world implication of the issue, rather than use the jargon. That might grate on people who do know the jargon.

For example, I want the consultant to criticize the volume delay curve equation. When I have Dennis talk about the note the consultant sent, he could say something like, “Here he questions how we calculate the delays from traffic congestion.” Most people know what delay and traffic congestion mean. They don’t need to know how the model estimates the delay.

Issues To Use

I’ve come up with a few more issues I think I can use.

  • Parking cost – this would affect whether people drive or take the bus.
  • Pedestrians mode constant in the modal choice model – this would affect how many people walk instead for drive.
  • Ride sharing – this would affect car pooling. This might include newer services like Uber or Lyft.
  • Trip distribution exponent – this would affect where people would go to work or shop.
  • Cycling – I plan to use a reference to cycling elsewhere in the revised script, so I wouldn’t want to use it here.

I’ll need to work on these issues some more before I go ahead with my rewrite. I still might decide to do some more research.

You can watch the previous version of “The Barrier” here: https://dynamiclethargyfilms.ca/the-barrier/

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