April 15, 2025
All,
Today marks the transition of the role of Chair for the TRB Travel Forecasting Committee (AEP50). From the first day I stepped into this community — in the basement of the Washington Hilton — I made it a professional goal to lead this Committee, and it has been an honor to do so during this term.
The first thing I want to say as I exit this role is thank you to everyone who has trusted me with leading this community, served as my sounding board, lent their ideas and time, and invested their heart into the work of the Committee. Thank you for raising your hand. Thank you for laughing and crying with me. Thank you for standing outside locked rooms in protest with me. Thank you for your debate, ideas, endorsements, well wishes, and the many good times and laughs.
Over the course of my tenure as Chair, we shined a spotlight on the important issues that our community prioritized:
Exploring how our role in the planning process affects the equity of that process and its outcomes.
Acknowledging and grappling with the deep uncertainty that exists in the inputs to our modeling systems — and how we make decisions under those conditions.
Addressing not just forecasts for specific streets or transit lines, but understanding VMT as a whole and its elasticity, to support planning and policies that sustain our lives and the planet that sustains them.
Examining the appropriate role of AI in travel forecasting.
None of these questions or lines of inquiry have clear answers or even well-established analytical frameworks. The human judgment involved in weighing the environmental, technological, economic, political, and social variables at play is something that — at least for now — even the best LLMs cannot replicate.
It’s this thinking about the “whole” that drew me to the field in the first place, and it’s something I hope this community continues to embrace, even as our tools and data grow ever more powerful. The precision and accuracy of any tool are meaningless without the right context for decision-making.
I hope that the messages I leave behind with this community are:
Be curious, and ask questions about if, how, and when the technical analysis you've been asked to do is actually used.
Work on questions, processes, and analyses that matter. If the process isn’t serving its intended purpose, fix the process. Fixing the tool or analysis inside a broken process is time wasted.
Don’t get stuck in the analysis box that some people try to put you in. Refuse to be the monkey in the back of the room cranking out numbers to check a box that doesn’t affect people’s lives.
Don’t innovate just for innovation’s sake. Start with the simplest way to answer the question and go from there. Don’t assume you need a million-dollar ABM to answer a question — and also don’t assume you need any travel model at all.
Trustworthiness is your professional currency. Once lost, it is rarely regained. Don’t endorse things that haven’t earned it. Don’t allow your work to be presented as “fact” when it’s a “good estimate” that requires appropriate caveats. Say the thing that’s hard but true.
I hope I have — and will continue to — uphold these values of practicality, collegiality, and trustworthiness. And I encourage us all to offer checks and balances to one another if any of us veers off course.
That brings me to a very difficult paragraph to write: I can no longer endorse the work of the Transportation Research Board as trustworthy and will be stepping away from further involvement until I see appropriate remedies taken. While there has been widespread reporting about TRB canceling millions of dollars in research, I have more recently learned of and corroborated efforts to censor peer-reviewed scientific work at forthcoming TRB conferences, as well as a plan to “desk-reject” papers and presentations based on “administrative priorities.”
TRB’s actions call into question not only what research is seen or unseen, but also the trustworthiness of what is published and whether it has been manipulated. In a publish-or-perish, grant-hungry academic environment, power imbalances like this can — and likely will — lead to scientific distortion when institutions like TRB fail. This is not a problem that individual researchers can solve on their own. It will take the leadership of trustworthy institutions to uphold scientific integrity in the face of these pressures.
I’ve poured thousands of volunteer hours — regularly five figures of in-kind time each year over the past 20 years (totaling nearly $1M) — into supporting TRB’s work. I am devastated to see the organization compromise decades of trustworthiness in a matter of weeks. I empathize deeply with the staff who have worked to maintain scientific integrity while also trying to keep their jobs. My heart breaks for the researchers who have lost funding and academic venues for their critical work. I mourn not just the loss of our vibrant professional community, but the missed opportunity to improve the lives we set out to serve.
But please know: I am not going away, and I am not turning my back on this community or the problems it faces. I’m still here — just not at TRB (for now). My door is open.
In community,
Elizabeth Sall