Modern transportation planning requires not only proven tools but also innovative approaches that harness the power of data, analytics, and technology. As agencies face rising challenges, from shifting travel behaviors to freight demands, traditional trip-based travel models must evolve to deliver insights that are accurate, actionable, and cost-effective.

At RSG, we help clients navigate this complexity by combining advanced travel modeling techniques with new data sources and technologies. By integrating passively collected data and survey insights into modeling frameworks, we equip decision-makers with tools that are both rigorous and practical.

To explore how these approaches are shaping the field, we spoke with Bobby Wertman, a Managing Consultant at RSG who leads the development of travel demand models. Drawing from his experience with agencies across the United States, Bobby shared his perspective on the role of trip-based models today, how RSG is innovating with big data, and what the future holds for the transportation modeling industry through new community-focused events such as the Modeling Mobility (“MoMo”) Conference.

How is RSG using passively collected data to enhance trip-based modeling?

RSG has been at the forefront of using passively collected data in modeling frameworks. We frequently use an origin-destination pivot-based approach that updates the synthetic trip patterns created by trip-based models with passively collected data. This yields more accurate origin-destination patterns, which is especially valuable for freight and truck modeling, where traditional trip distribution models can fall short.

Passively collected data strengthens freight models, helping planners better align forecasts with actual shipping and distribution behavior.

For passenger vehicles, existing gravity or destination choice models are often quite capable of reproducing passenger vehicle trip patterns at the zone level, but freight is more challenging. Passively collected data helps fill that gap and offers a lower-cost option for agencies that may not have the resources to commit to a full household travel survey. While passively collected data cannot completely replace surveys, it can serve as an important tool to update travel demand models.

What role do trip-based models play in today’s transportation planning toolkit?

Trip-based models have been around for many years and have evolved in many ways since they were first conceived. They remain important tools for everything from regional- to project-level planning. That said, they have limitations as is the case with all models. The key is for planners to view them as a tool in a much larger toolbox. Planners should avoid over-relying on a single approach and instead focus on choosing the tool or tools that best support the planning question at hand. That’s how RSG approaches each project/problem on behalf of our clients.

Can you share a project where RSG’s modeling work helped a client make a smarter decision?

One example comes from Anchorage, where we’ve worked on a trip-based travel demand model for more than a decade and through multiple development iterations. The model has been applied in many contexts, and in one case we used it to demonstrate sensitivity to intersection control delay in the network. Some stakeholders were hesitant to trust the results, but the model showed realistic outcomes that challenged conventional expectations and proved useful in decision-making.

Another example is our work with freight modeling. In one region, the original model produced unrealistic truck destination patterns. However, by integrating a pivot-based approach with passively collected data, we achieved far more accurate results. Instead of favoring central locations, the updated model reflected how distribution centers are located near highways and was much more consistent with real-world behavior.

How do you see trip-based models evolving as agencies face challenges such as electrification and changing travel/work patterns?

Trip-based models will continue to evolve with planning and policy needs. About 10-15 years ago, travel models were becoming increasingly complex. That trend made them difficult for agencies to understand and maintain. Today, we’re seeing a “re-simplification” among our clients, with a focus on usability and clarity.

At the same time, models are expanding their utility to address issues like telecommuting and e-commerce. For example, work-from-home and home delivery trends are critical to understanding the post-pandemic travel landscape. As modelers, we can build in the framework to analyze electrification and telecommuting, but those insights depend on robust household travel surveys to provide the data. Ultimately, the key is ensuring regions collect strong behavioral data so models remain relevant.

Trip-based models remain a vital tool for planners amid continued changes to how and where people work, shop, and otherwise travel.

We’re also seeing lasting shifts in daily travel patterns. Instead of distinct AM and PM peaks, many regions now show a single, bell-curve-shaped distribution throughout the day. That’s a major change, and one that our models need to account for moving forward.

You’ve helped organize this year’s MoMo (Zephyr) event. Why is it an important gathering for the modeling community, and what conversations excite you most?

MoMo is new this year, but the people behind it are long-standing members of the modeling community. What makes this event unique is its focus on building and sustaining community. It’s not about publications or papers; it’s about connecting practitioners, students, and emerging professionals.

The goal is to create a home for people tackling today’s mobility challenges, and to foster mentorship and knowledge-sharing across the field. I’m most excited about that sense of community and the opportunity for people to connect, learn, and collaborate. My role has been on the planning committee, supporting graphic design, and contributing to broader program discussions. It’s a true team effort, and we hope MoMo continues to grow as a space where the modeling community comes together.

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Bobby Wertman is a Managing Consultant at RSG with extensive experience developing travel demand models and integrating passively collected data into planning frameworks. He has worked with agencies across the United States to design and apply models that improve regional and project-level decision-making, drawing on expertise in household travel surveys, model architecture, calibration, validation, and application. He excels at translating complex data into actionable strategies, helping clients better understand travel behavior, evaluate policy options, and make more confident, data-driven investment decisions. Connect with Bobby »