Under requirements for long-range transportation planning, state departments of transportation and regional metropolitan planning organizations are required to have a multimodal transportation plan with a minimum time horizon of 20 years. Because manufacturers and shared fleet operators suggest that connected and autonomous vehicles (CAVs) will be present on the highway system in significant numbers well before then, the planning community requires procedures and methods to address the potential positive and negative direct and indirect outcomes from their deployment.
In response to this, TRB’s National Cooperative Highway Research Program (NCHRP) selected RSG as part of a team to develop guidelines for implementing travel forecasting models to address travel behavior and system performance changes associated with CAVs. The research assessed current travel forecast modeling frameworks for their applicability and potential for inclusion of CAVs in the transportation system, including guidance for trip-based, disaggregate/dynamic, and strategic modeling systems. This study included identification of gaps in current modeling frameworks, prioritized critical elements required to model CAVs, developed a draft framework for modeling CAVs, vetted the framework with peers in the modeling community, and developed guidelines for data collection and implementation of the framework. The framework included focus on both system performance (supply side) variables and travel behavior variables.