ActivitySim is everything you know and love about activity-based modeling. But better. Much better.

Meet ActivitySim—a state-of-the-practice activity-based modeling platform that is always improving. It is open source, purpose-built, and grounded in the principles of collaboration and modern software engineering. 

The advantages to activity-based modeling have been known for quite some time. But the Association of Metropolitan Planning Organizations (AMPO) saw an even deeper industry need. They created a consortium of member agencies to drive this project. Their mission? To build and maintain advanced, open-source, activity-based travel behavior modeling software based on best software development practices—and to do it at no charge to the public.

And, just like that, ActivitySim was born.

Graphic showing the logos of all ActivitySim consortium members below the logo for the Association of Metropolitan Planning Organizations (AMPO). The logos below AMPO include Ohio Department of Transportation, San Francisco County Transportation Authority, Puget Sound Regional Council, Metropolitan Council, Atlanta Regional Commission, Southeast Michigan Council of Governments, San Diego Association of Governments, Chicago Metropolitan Agency for Planning, Metropolitan Washington Council of Governments, Oregon Department of Transportation, and Metropolitan Transportation Commission.

One of the best parts? It's always getting better.

Open source technology is a huge movement. That's no secret. But, an open source activity-based modeling platform changes the very landscape of modeling. The deeper collaborative nature of ActivitySim being open source makes it state-of-the-practice and, perhaps even more impressively, means it is always improving. Each user has a say in its development and future direction.

You might be wondering how this works. It's simple. As additional members join the ActivitySim consortium, the use and development progresses. As this occurs, ActivitySim becomes even more robust.

This technological advancement then comes full circle, helping all the consortium members with its improvements. Members benefit in several ways:

We're leading the first full travel demand model conversion to ActivitySim.

Several organizations have used and benefitted from ActivitySim. But so far? Only in parts. Until now.

SEMCOG (Southeast Michigan Council of Governments) is the metropolitan planning organization for the region of Southeast Michigan that includes Detroit. Given the size and diversity of the region they oversee, they needed a practical and functional activity-based travel demand model capable of robust policy analyses. They wanted it to help answer questions unique to their region and provide greater demographic, spatial, and temporal detail than their trip-based model.

SEMCOG joined the ActivitySim consortium and, in the fall of 2019, we began to work with them on their model. By then, ActivitySim had advanced to the point where it could be used as the base model for the region. So, SEMCOG opted to completely adopt ActivitySim as their travel demand model with a full model conversion. They are pioneers as the first agency to do so and we're thrilled to be helping them.

SEMCOG is following a two-phase approach to get the model up and running quickly and help train staff on its use and functions. Phase I was completed in 2020 and Phase II is currently underway and expected to be completed by the spring of 2022. Learn more in our white paper »

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Check out our ActivitySim
white paper.

ActivitySim has changed the very landscape of modeling. Learn more about how it started, where it's headed, and how it is helping agencies tackle some of their biggest challenges.

We're activity-based modeling experts and the lead developers and architects of ActivitySim.

We built it. We use it. And we would love to chat with you more about the ways ActivitySim may be able to help you get the answers you need.

Joel Freedman


David Hensle


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