Our History

Zephyr grew out of informal conversations at Transportation Research Board (TRB) Annual Meetings into a formal foundation for advancing travel analysis methods. This is the story of how that happened.

The Spark

Starting with ideas shared at TRB Annual Meetings, a small group of practitioners and researchers took the initiative to turn years of hallway conversations into action, building the foundation, community, and momentum that became Zephyr.

Billy Charlton
Gregory Erhardt
Brian Gardner
David Ory
Elizabeth Sall
Joan Walker

Founding (2017)

January 8, 2017

“From Ad-Hoc to Organized”

A TRB Annual Meeting workshop marked the next step in establishing the Zephyr Foundation. Attendees worked in teams to scope out eight potential projects — on reproducible research, before-and-after studies, community-owned modeling software, forecasting uncertain topics, model benchmarking, data wrangling, network specifications, and data standards — that would go on to seed much of Zephyr's later work, from ActivitySim and software badging to GMNS and shared data standards.

May 13, 2017

“Zephyr's First Year”

A follow-up workshop at the TRB Planning Applications Conference introduced Zephyr's initial Board of Directors, elected by the Founding Stakeholders, and featured a "Project Shark Tank" pitch session for the ideas scoped in January.

August 10, 2017

The effective date the IRS would later recognize, retroactively, for Zephyr's 501(c)(3) tax-exempt status.

November 3, 2017

The initial Board of Directors formally adopted Zephyr's bylaws at its organizational meeting, establishing the governance structure the Foundation still operates under today.

Zephyr’s Founding Stakeholders — the industry leaders who provided early guidance, shaped the organization’s initial direction, and elected its inaugural Board — made all of this possible. Organizational affiliations are provided for identification purposes only and do not imply endorsement or official representation by their employer or institution.

Alexei PozdnukhovUniversity of California, Berkeley
Aruna SivakumarImperial College
Beverly ScottBeverly Scott and Associates
Chandra BhatUniversity of Texas
Clint Daniels[former] San Diego Association of Governments
Dan FlorianINRO Software
Eric AndersonMaricopa Association of Governments
Eric MillerUniversity of Toronto
George NaylorSanta Clara Valley Transportation Authority
Greg GiaimoOhio Department of Transportation
Hani MahmassaniNorthwestern University
Howard SlavinCaliper
Julie DunbarDunbar Transportation
Kay AxhausenETH-Zurich
Moshe Ben-AkivaMassachusetts Institute of Technology
Pat MokhtarianGeorgia Institute of Technology
Rick DonnellyWSP-PB
Rosella PicadoWSP-PB
Stephen LaweResource Systems Group
Steve PeronePTV
Therese McMillanLA MTA
Vladimir LivshitsMaricopa Association of Governments

Early Years (2018–2020)

With a Board and bylaws in place, Zephyr spent its first few years turning founding ideas into working programs:

2018

The Software Badging effort was established, and the GMNS Project Management Committee began the multi-year process (running through 2024) of defining, drafting, and revising the General Modeling Network Specification.

January 2019

The first project management group meetings convened at the TRB Annual Meeting, covering Fast-Trips, GMNS, Open Science, and Software Badging — alongside the first Zephyr TRB Reception.

February 2019

Zephyr officially attained 501(c)(3) tax-exempt status, retroactively effective to August 10, 2017.

2019

The first Zephie Awards were presented, recognizing Julie Dunbar and Joe Castiglione, and Zephyr documented its first formal Board elections process.

Late 2019

Software Badging awarded its first project.

2020

The Technical Achievement Award and Impactful Research Award were presented for the first time, recognizing the SACOG Technical Team and Michel Bierlaire (for Biogeme).

May 2020

As the pandemic reshaped how the community could gather, Zephyr held its first virtual Learning Session — including an early introduction to ActivitySim — a format that's remained part of Zephyr ever since.

Growing Up (2021–2025)

As Zephyr’s activities and membership grew beyond what an all-volunteer Board could run alone, the Foundation brought on new activities and its first paid staff:

Late 2022

NSF Funding Awarded

A joint team spanning ASU, MTC, USF, and Ohio State was awarded a strategic grant for NSF funding to support GMNS multi-modal network initiatives.

December 2022

GMNS & Network Wrangler Convergence

A pivotal coordination milestone aimed at bringing the GMNS data specification and Network Wrangler closer together, establishing shared technical support and mapping out a unified roadmap for network scenario management.

2023

TMIP Integration

The Travel Model Improvement Program (TMIP) — including its 1,800-subscriber listserv and 20 years of archived webinars and presentations — transitions to Zephyr, a major step forward in establishing Zephyr as a central knowledge-sharing hub and listserv administrator for travel demand forecasting professionals.

2024

MoMo Fiscal Sponsorship

Zephyr becomes the fiscal sponsor for MoMo, providing a nonprofit home to handle contracts, venue booking, and funding for the volunteer-organized conference.

2025

ActivitySim Transition

Zephyr becomes the new administrative home for ActivitySim, taking over from AMPO and overseeing a $490,000 budget and 14 participating agencies across the US, Australia, and Canada.

September 3, 2025

Joe Castiglione was hired as Zephyr's first Executive Director to lead the organization's day-to-day work.

September 14–17, 2025

Inaugural MoMo Conference

The first MoMo (Modeling Mobility Conference) was held in Minneapolis, Minnesota, at the McNamara Alumni Center of the University of Minnesota (Twin Cities), bringing together over 300 modeling community members.

Where We Are Today

Many of the projects scoped in that first 2017 workshop are now established Zephyr activities, carried out by member-driven committees and guided by Zephyr’s Board and Executive Director.

Get Involved

Zephyr is a community effort — join as a member, support our activities, or say hello in the Zephyr Forum.

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