May 10


4 Suggestions for the Future of ITE’s Trip Generation

By Mike Spack

May 10, 2016

ITE, Person Trips, Trip Generation, TripGen,, urban trip generation

Traffic in Seoul South KoreaHere is a link to an email I received from ITE about the future of their Trip Generation effort.  Basically, they are looking at modernizing their Trip Generation system to include Urban Trip Generation and Person Trips.  They’ve set up several committees to start to figure it out.  Hopefully they develop a robust, filterable system like TRICS.  A fundamental issue that needs to be addressed is how much modern, relevant data is included in their dataset.

I also love the idea of moving towards person trips to pin down trips made by all modes, but I’m unsure how to cost-effectively collect this data.  I’ve posted several times on the ITE Community asking how others are collecting person trip data – with no response.  I hope ITE will fund this type of data collection or promote government agencies/researchers collecting more of this data.

Here are 4 More Suggestions for ITE to consider:

  1. Tiered subscription pricing. Tiered subscription-based pricing so very occasional users can pay a reasonable fee to access the data while heavy users can pay a bigger annual fee that is actually cheaper for them per use.  There are many cities out there that need to access this database once or twice a year.  The days of making them buy a $412 book should be over.
  2. More frequent updates.  Because traffic studies are based on this dataset, agency staff need the ability to go back and double check the calculations as part of their review.  This probably means we can’t have a living dataset that is altered every time new data is submitted. However, there’s no reason a new edition can’t be published each January 1st.
  3. Access to previous Editions of Trip Generation.  Whether the dataset is published on a ten-year cycle, a four-year cycle, or an annual cycle; we’ll end up with a traffic study submitted with data from one Edition that gets approved after the next Edition was released.  Reviewers need to be able to access the most current dataset as well as the previous dataset.  Researchers would also like the ability to access more than just the previous dataset.
  4. Provide incentives for professionals to upload trip generation data.  I am happy to freely share our data at through a Creative Commons license, but I don’t see a reason to submit it through Transoft’s OTISS system who then profits from the data AND charges me back to access it.

I hope to get an opportunity to discuss the future of Trip Generation data at the ITE Annual meeting as advertised.

  • Hey Mike,

    I think a living dataset is actually EXACTLY what we need. You mentioned being able to filter existing data, isn’t that a custom set? How is that any different than having a living dataset which updates as soon as new information is available. Either way you’re not using the ‘Edition’ dataset anymore. You’re using a custom set of data based on the needs of your study and when it occurs. As long as a record exists of exactly which points your calculation was based on, then it is replicable and verifiable. As long as you’re following an agreed upon ‘standard’ for coming to your result then the lawyers should be satisfied.

    ITE should shift from charging for the data and move in the direction of the ‘best practices’ for HOW to filter data and what criteria to use to make our calculations statistically significant. TRICS gives excellent guidance in their user guide for filtering the database. ITE could do similar.

  • Adam – You are correct that a living/filterable dataset would allow the practitioner to provide more accurate forecasts, which should be our goal as traffic engineers/planners. There are jurisdictions that reference the average rates from ITE’s Trip Generation Manual in their ordinances/codes. Those jurisdictions would need to change their approach. Instead of a precise trip generation rate that is agreed on advance, a bespoke approach would be required for each study. Best practices could certainly be developed, but it’s a lot easier to refer back to “the average rate” in a courtroom when a developer’s engineer is contradicted by the government agency engineer (or vice versa). The real world is definitely gray, but I’ve met agency engineers and attorneys who prefer black and white. Mike

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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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