Incremental Modeling Developments in Sacramento, California: Toward Advanced Integrated Land Use-Transport Model

The regional transportation planning agency in Sacramento, California, is taking a three-pronged approach to updating its land use-transportation forecasting models: developing a long-term model design, improving existing models toward that design, and collecting data that can be used to support the existing models while the new design is being developed. The advanced integrated model design contains a tour-based travel model involving microsimulation of individual tours of synthetic households, a microsimulation-based land development model, and a spatial input-output model of the regional economy. The existing models consist of a land use model based on the MEPLAN model, a traditional four-step model of transportation demand improved with the addition of an automobile ownership submodel and joint consideration of mode and destination for work trips, and an interactive neighborhood-level parcel allocation system. The process described is one of improvement of current models and of moving toward a new model design while the agency faces ongoing modeling needs and uncertain budgets.