This edition of the ITE Journal features several terrific articles focused on Intersection Improvement and Design. One of the things I like most about our monthly publication is the depth and breadth of technical content that we continue to feature, and it’s because of you—our members—who continue to produce interesting and exciting articles!
While I’m always up for a great conversation about signalization, roundabouts, or unconventional intersection designs, my column this month leans into a topic that shines much earlier in the process: the trip generation data that many of our practitioners utilize to help them in their planning and development efforts.
As I’m sure many of our readers know, ITE’s Trip Generation Manual (TGM) provides trip generation rates for various land use and development types. The planner can add local adjustment factors and treat mixes of uses with ease. The data from this manual can be used for many purposes: an early step in the transportation forecasting process, help determine whether further traffic impact analyses are needed, and help to better interpret socioeconomic and demographic data for a particular location by adding an additional layer of mobility information.
ITE relies heavily on the voluntary submittal of data from the transportation community to produce this valuable reference. We are actively collecting data right now, in preparation for releasing the 12th edition roughly 1 year from now (Summer 2025).
We need your help by submitting data for all types of land uses; for urban, suburban, and rural settings; for different modes including vehicle, pedestrian, bicycle, transit, and truck; and even for unique cases like pass-by and diverted trips. In my April column, I talked a lot about the updated Manual on Uniform Traffic Control Devices. Its frequent acknowledgment that “not all situations are the same” was a key point in my column, because context sensitivity is critical in today’s planning and engineering environment.
Here we are now in August, and I’m once again going to bring up that point, but targeted instead at the TGM and how it’s vitally important we consider that “standard trip generation rates” are constantly challenged by the “not all situations are the same” paradigm. And the best way to overcome the context challenge is by collecting greater volumes of data.
A single data point for a land use scenario is only valuable for the conditions in which it was collected. But 20 or 30 data points for that land use now begins to normalize
for the differences—and shows the range of possibilities that likely exist depending on specific context. We need more ranges for planners and engineers to work from. We need more variability in our standard data and more data to make decisions from.
As I said, ITE relies heavily on the voluntary submittal of data from the transportation community to produce this valuable reference. So please, we need your help to continue to improve this resource and to ensure delivery of the most accurate and up-to-date information available.
If you have conducted trip generation counts of any kind—large or small—we encourage you to submit data at your earliest convenience! You can visit our collection site at https://www.ite.org/tripgenportal, or you can email us at tripgen@ite.org with questions or submissions. The industry thanks you for your contributions!